Teenagers. Rude, lazy, secretive...and that's just the nice ones.
Actually they're not all bad. Many are hardworking types dedicated to their chosen career paths.
Take teenage footballers for instance. It takes more than mere talent to make it at a big club. Just to prove that point, we've picked out the 50 best teenage footballers in the world.
Souleymane Coulibaly was the top scorer in the 2011 Under-17 World Cup for the Ivory Coast, scoring nine goals in only four games, including a hat-trick against Brazil's youngsters.
Tottenham swooped to take Coulibaly from the Italian club Siena, and he has subsequently impressed in the White Hart Lane youth system.
Harvard Nielsen was only 16 years old when he made his debut for Valerenga and became the club's youngest ever player.
Now 19, Nielsen can play as a striker or winger and signed for Red Bull Salzburg in 2012. He made his debut for Norway against Hungary last year and scored a goal on his debut.
Eighteen-year-old winger Memphis Depay broke into PSV Eindhoven's first team last season.
Dick Advocaat has used Depay regularly this season, both in Eredivisie and in Europe. The wide player has eased the pain after the loss of Zakaria Labyad last summer.
It's perhaps true that the 19-year-old Ross Barkley hasn't quite made the progress that was expected of him at Everton, with his fast track to the top being slightly derailed by a broken leg in 2010.
Nevertheless, great things are still expected of the player, and he was a big success earlier this season while on loan in the championship with Sheffield Wednesday before being recalled to Everton.
Aged just 17, the Bochum midfielder Leon Goretzka has already made his 19 appearances this season in the second tier of German football.
Capped by Germany at under-16, 17 and 19, Goretzka is a powerful figure at 6'2" and with pace to match, he is very difficult to stop when running with the ball.
Some fine players have come though the ranks at Crewe Alexandra, and Manchester United's 18-year-old midfielder Nick Powell looks set to become a welcome addition to their alumni list.
Powell was 16 when he made his debut for Crewe in 2010, and the following season, he became first choice, scoring 14 goals to attract the attention of Sir Alex Ferguson.
With his frightening acceleration, Lazar Markovic looks like he's going right to the top and fast.
Aged 18, the Partizan Belgrade forward has already notched up 60 appearances and 13 goals for his club, as well as winning six caps for Serbia, scoring his first goal against Chile in 2012.
Like Cesc Fabregas before him, Arsenal's Hector Bellerin came to London from Barcelona in search of first-team opportunities.
Arriving at the club as a right winger, the 17-year-old has been converted into a marauding right-back and has been earning rave reviews in the Arsenal youth sides.
The 19-year-old Senegalese forward Moussa Konate scored five goals for his country during the 2012 Olympics tournament.
His exploits prompted the Russian-club FC Krasnodar to pay €2 million to Maccabi Tel Aviv for Konate's services.
Having brought the likes of Gareth Bale, Theo Walcott and Alex Oxlade-Chamberlain through their ranks, it looks as if Luke Shaw will be the next top player produced by the Southampton Academy.
The attacking left-back is currently gaining some valuable Premier League experience at Southampton, but if the club are relegated, it would be no surprise to see the giants of the EPL competing for the 17-year-old's signature.
You may have seen Lucas Piazon missing a penalty for Chelsea recently in their 8-0 drubbing of Aston Villa.
Greater things are certainly expected for the 18-year-old Brazilian at Stamford Bridge, who was snapped up from Sao Paulo and has been compared to Kaka.
The young Peruvian-forward Andy Polo made his debut for Universitario de Deportes at 16 and quickly became an important member of the squad over the next two seasons.
His pace and finishing skills attracted the interest of Genoa, who bought the player last year and allowed him to remain in Peru to further enrich his football education.
Suso was signed for the Liverpool academy from Cadiz by their former manager and fellow Spaniard, Rafa Benitez.
The 19-year-old has made his way into the Liverpool first team this season, impressing in his 17 appearances.
Tomas Kalas was signed by Chelsea for £5.2 million in 2010 and was loaned for the 2011-12 season to Vitesse, where he has continued to play this term.
The 19-year-old can play at centre-half or right-back and earned his first international cap for the Czech Republic against Slovakia last year.
Jon Toral is a 17-year-old central midfielder who left Barcelona in search of first-team football at Arsenal. Remind you of anyone?
In truth, Toral is a more powerful figure than Fabregas at 6'3" and a box-to-box player, but comparisons are bound to be made once Toral makes his breakthrough at Arsenal.
These days, Manchester City are not just signing established superstars for multimillion-pound fees and are increasingly looking to recruit the world's most talented young players.
One such youngster is the 18-year-old Denis Suarez. The Spanish midfielder was signed from Celta Vigo in 2011 and has appeared for City in the League Cup.
How will Santos replace Neymar when he eventually moves to Europe? The answer could already be at the club.
Victor Andrade made his Santos debut at 16 last June and went on to make 14 appearances for the club. Able to play as a left-winger or striker, the 17-year-old has a €50 million release clause in his contract.
Given the high-profile signings that have been made by Malaga in recent seasons, it is not as easy for young players to make the breakthrough at the club as it once was.
But one who has forced his way through is Juanmi.
The little 19-year-old striker became the club's youngest ever scorer at 16 and has so far notched eight goals for the club as he battles to become a permanent starter.
The Argentine-forward Juan Iturbe began his career in Paraguay with Cerro Porteno, making his debut at 16.
Iturbe impressed sufficiently for Porto to make a move for him in 2011, and he has recently been loaned to River Plate. The diminutive dribbler was capped by Paraguay in 2009, but as it was a friendly appearance, he was able to switch allegiances to Argentina.
The 18-year-old Dane, Viktor Fischer has scored five goals so far this season for Ajax and made his Champions League debut.
Inevitably likened to his fellow Dane at Ajax, the midfielder Christian Eriksen, Fischer is actually a striker. But the one thing they do have in common is winning a full cap, with Fischer having made his Denmark debut back in November.
Don't make the mistake of thinking that Chelsea only signed the 19-year-old Thorgan Hazard to keep his more famous brother Eden company in London.
Thorgan is a serious prospect in his own right. An attacking midfielder or winger like his brother, Hazard is currently on loan to Zulte Waregem in his home country of Belgium.
Tonny Trindade de Vilhena won the U-17 European Championships with Holland in 2012 and was the tournament's joint top scorer with three goals.
Making his debut in 2011, the 18-year-old has made 15 appearances for Feyenoord, and the attacking midfielder has a brain that is just as quick as his feet.
Zakaria Labyad made his debut for PSV Eindhoven at 17 in 2010, and by the 2011-12 season, the little attacking midfielder had established himself as a regular starter for the club, scoring 10 goals.
Labyad was signed by Sporting Lisbon last summer, before switching allegiances from the Netherlands to play for Morocco at the London Olympics. He has since represented Morocco at senior level and is now battling to secure a regular starting birth for Lisbon.
Already labelled as the "Croatian Messi," the 16-year-old Alen Halilovic has become the youngest player this season to score a goal in the Croatian top division and made his Champions League debut for Dinamo Zagreb.
With great dribbling ability and an eerily accurate shooting ability from long range, it's no wonder that the Messi comparisons have been made.
Jose Campana captained the Spanish Under-19 side to success at the European Championships and may one day grace the senior side.
Campana broke into the Sevilla side last season and the 19-year-old is a technically gifted player who can operate in both midfield and defence.
Of all the young players that are included on this list, it is Adryan of Flamengo who wins the title for being the most fresh-faced.
Despite his pre-pubescent appearance, Adryan is actually a relatively mature 18-year-old, and the exciting attacking midfielder has made some 25 appearances for Flamengo.
The audaciously skillful Dinamo Zagreb star Mateo Kovacic became the second-youngest goal scorer in Champions League history when he netted against Lyon last season.
An attacking central midfielder, he has been likened to Luka Modric, but with a more powerful physique, he may achieve even more in the game.
Bruno Mendes started his career at Guarani, only to be quickly snapped up by Botafogo.
The 18-year-old striker hit six goals in six starts for Botafogo, and the gangly youth could prove to be a very dangerous player as he physically matures.
Samuel Umtiti made his debut for Lyon in the second half of last season and quickly won the confidence of Remi Garde.
After a successful U-19 European Championships for France in the summer, Umtiti has switched from left-back to centre-back in the Lyon team this season.
Andreas Cornelius has been making waves in the Danish Superliga this season, scoring 14 goals in 20 games.
Denmark have been quick to cap the 19-year-old, who has impressive skills for a striker that stands tall at an imposing 6'4".
Able to play at both left-back and left-midfield, Lucas Digne has established himself as a regular for Lille so far this season, having made his debut in 2011.
Fast and impressive going forward, the 19-year-old defender has been capped by France at U-16, 17, 18 and 19 levels.
Valon Berisha turned down the likes of Manchester City and Aston Villa to sign for Viking in his native Norway, and he was awarded with a debut in 2010.
The 19-year-old midfielder signed for Red Bull Salzburg of Austria last summer and has already won eight caps for Norway.
It's tough for a teenage goalkeeper to get a game at the top level, but at 6'6" tall, Stefanos Kapino certainly has the physical attributes to play with the big boys.
The 18-year-old keeper made his debut for Panathinaikos in 2011 and has already won a cap for the Greek national team.
At 18 years old, Josip Radosevic has only played 15 times for Hadjuk Split and yet has already one a full cap for Croatia.
The youngest player to have appeared for the Croatian national team, Radosevic is a tough-tacking and tenacious defensive midfielder.
Angelo Henriquez burst onto the scene at Universidad de Chile last season with 15 goals in 28 games, earning him a move to Manchester United.
Now United fans will get a chance to see exactly how good Henriquez is in the Premier League, with the striker having just signed on loan with Wigan until the end of the season.
It is rare that central defenders make their debut at 16, which just shows the faith that Saint-Etienne have in Kurt Zouma.
After an impressive campaign in his debut season, Zouma has struggled with an injury this term, but at 18, he has plenty of time on his side.
The 18-year-old left-back Jetro Willems was a surprise choice in the Holland squad for Euro 2012 and eventually played in all three of the group games, before his country was eliminated.
The PSV defender, who started his career at Sparta Rotterdam, has already won eight caps for the Netherlands.
The 18-year-old Argentine-forward Lucas Ocampos is a sensational dribbler, who impressed enough during his debut season at River Plate for Monaco to pay a cool €15 million for his services.
Mainly used as a substitute this season, Monaco are currently set for promotion from Ligue 2, giving Ocampos the platform to display his outrageous skills in one of Europe's top leagues.
With Manchester United currently lacking a powerful presence in central midfield, you wonder how Sir Alex Ferguson managed to let a player as talented as Paul Pogba slip through his hands.
The 19-year-old Frenchman made his debut for United last season but left in the summer for Juventus on a free transfer. The midfielder has made 15 appearances for the Old Lady this season.
Raheem Sterling was just 15 years old when Liverpool signed him from QPR back in 2010.
Making his debut last season, Sterling has cemented a regular starting berth under Brendan Rodgers, as well as making his debut for England and has dazzled with his inventive wing play.
The Argentine winger Ricardo Centurion can play on either flank and has been compared to his compatriot Angel Di Maria.
Centurion was recently called up to the Argentina squad after impressing this season in his 17 appearances for Racing.
The next superstar to emerge from Barcelona's conveyer belt of talent could well be Gerard Deulofeu.
Breaking into Barcelona's first team isn't easy, even for a player with the dribbling ability of the 18-year-old forward, but Deulofeu has so far made five first-team appearances while scoring 12 goals in 16 games this season for Barcelona B.
The versatile 19-year-old Raphael Varane can play at centre-back or in a defensive-midfield role. Starting his career at Lens in 2010, he was signed by Real Madrid for €10 million after his first season.
Varane made 15 appearances for Real last season and has been featured on 12 occasions already during this campaign, including five games in the Champions League,.
Pescara fans could have been forgiven for thinking that the club would struggle to replace Marco Veratti when the club sold him to Paris Saint-Germain, but in the form of Juan Fernando Quintero, they've managed to fill the gap.
The 19-year-old Colulmbian playmaker has impressed in Serie A this season, having been signed for just €3 million.
The 19-year-old midfielder Adam Maher has won two senior caps for Holland after being selected for the provisional 36-man squad for the European Championships in 2012.
Maher scored 11 goals last season for AZ and was voted Holland's young player of the year.
The Manchester City centre-back Matija Nastasic is still only 19 but is already well-traveled.
Having started his career at Partizan, Nastasic was transferred to Fiorentina, where he impressed sufficiently last season for City to make a multimillion deadline-day move for him. Nastasic was recently named as the club's player of the month for November.
Alex Oxlade-Chamberlain has already achieved a lot for a 19-year-old, having become the youngest English scorer in the Champions League and winning nine caps for England.
Oxlade-Chamberlain played well enough in his debut season for Arsenal to be called up to England's Euro 2012 squad and the powerful forward looks set to win many more caps.
The 18-year-old French-striker M’Baye Niang burst onto the scene for Caen in 2011, making his senior debut at 16.
Immediately attracting the interest of Europe's top clubs, the tall and skillful striker was eventually signed by AC Milan at the start of this season and has already made his Serie A debut for the club and scored his first goal for the Rossoneri in the Italian Cup.
If Chelsea ever want to find a direct like-for-like replacement for the departed Didier Drogba, then they need only look towards their loan starlet Romelu Lukaku.
Still only 19, the 6'3" Lukaku has impressed on loan at West Brom, where he has scored seven goals in the first half of the season.
It's fair to label Julian Draxler an early-achiever. Upon making his debut for Schalke in 2011, he became the fourth-youngest Bundesliga player ever, and then a week later, he became the second-youngest player to start a game in the German top flight.
Now aged 19, Draxler has made 86 appearances for Schalke, in which he's impressed enough to have been named in Germany's provisional squad for Euro 2012. With three caps for his country already, the attacking midfielder looks like he's set for the very top.