As a fan, there's nothing more frustrating than seeing a player who is undoubtedly talented fail to perform. What's even more frustrating is when supporters see that player flourishing in another club's colours.
Arsenal have had plenty such cases. Some of these players were simply never able to replicate the form they'd shown with previous clubs in north London. Others had to leave Arsenal in order to produce their best.
Go to the next slide to see who has made this regret-filled Arsenal XI, lining up in an admittedly adventurous 4-4-2 formation.
Vito Mannone has been one of the breakout stars of this Premier League season.
His time at Arsenal was relatively undistinguished. He suffered from enormous competition, and he spent most of his time behind the Polish pair of Wojciech Szczesny and Lukasz Fabianski in the pecking order.
However, this summer, Mannone decided he'd had enough of playing second (or even third) fiddle. He opted to move to Sunderland, where he has established himself as the No. 1 since taking over from the injured Keiren Westwood.
His eye-catching displays have helped the Mackems climb the table. If they are to stay up this season, Mannone will be crucial to their survival.
When William Gallas arrived at Arsenal from Chelsea in 2006, he was widely regarded as one of the best centre-backs in the world.
Gallas' status was underlined by the fact that he was chosen to inherit the Arsenal captaincy from Thierry Henry in 2007. However, that's where it all started to go wrong. Gallas was not a natural leader: The sight of his on-field strop at St. Andrews in 2008 still haunts the Arsenal fans.
Gallas' relationship with the fans never recovered, and his performances on the pitch were a shadow of what he produced in the blue of Chelsea.
Gallas was predominantly a centre-half, but in his time at Stamford Bridge he showed the versatility to play in either full-back role. In this XI, he will play on the right.
Matthew Upson was a promising defender at Arsenal, who struggled for first-team opportunities. Eventually, he sought pastures new, and his career took off. He became a stalwart for both Birmingham City and West Ham United.
The high-point of his career arguably came in 2010, when he was a starter for England in the World Cup.
Upson may not have been a true superstar defender, but it's certainly fair to say his best performances came away from Arsenal.
Mikael Silvestre has won the Champions League.
From his performances at Arsenal, you could never tell. Silvestre arrived towards the end of a distinguished career, but he was clearly a shadow of the player he had once been.
His history with Manchester United also did little to endear him to the Arsenal fans. In Arsenal colours, Silvestre became a byword for calamitous defending.
Andre Santos departed Arsenal as something of a comedy figure. His error-prone on-field performances were matched by his off-field gaffes, such as exchanging shirts with Robin van Persie at half-time of a crucial clash between the Gunners and Manchester United.
However, it's not hard to see what attracted Arsenal to the former Fenerbahce man: Prior to signing for Arsenal, Santos was a fully-fledged Brazilian international.
The move to London marked a turning point in Santos' career. The chances of him being recalled to the Brazil squad are now significantly slimmer than Santos himself.
Gervinho is a conundrum of a footballer.
One is never quite sure what he is going to do. For defenders, it's bewildering and terrifying. For team-mates and fans, it can be equally frustrating.
Gervinho arrived at Arsenal as a champion of Ligue 1, but he failed to reproduce that exhilarating form in England.
However, he is now flourishing again under his former Lille boss Rudi Garcia at Roma, while Arsenal fans have been left wondering why it never happened for him in the Premier League.
Arsene Wenger was certain that Julio Baptista was the natural heir to Patrick Vieira.
In 2005, he relentlessly pursued the muscular Brazilian, but he lost out to Real Madrid. However, a year later, he finally got his man. Baptista arrived on a year-long loan deal, with a view to a permanent transfer.
In Spain, Baptista had earned the nickname "The Beast" for his all-action displays. He was an irrepressible force and a clinical goalscorer.
However, at Arsenal he was primarily used as a substitute. Wenger attempted to convert him to a traditional No. 9 with limited success.
Although he is generally regarded as a flop, Baptista will always be fondly remembered for a stunning four-goal haul at Anfield.
Few Arsenal signings have excited like the arrival of Andrey Arshavin. His deadline day move from Zenit St. Petersburg in 2009 promised much.
Arshavin was the darling of Russian football and one of the undoubted stars of EURO 2008. The beginning of his Arsenal career was impressive too, with a four-goal display at Liverpool particularly eye-catching.
However, his form quickly tailed off. With question marks over his fitness and attitude, Arshavin was eventually relegated to the occasional cameo. Last summer, he was released and allowed to rejoin Zenit on a free transfer.
Arshavin would be something of a gamble in a central midfield role but at least he wouldn't be stuck out on the wing.
Jose Antonio Reyes was the club's record signing when he arrived in Sevilla in 2004. However, he never fulfilled his obvious potential with the Gunners.
In Seville, Reyes had built a reputation for electric dribbling and lethal finishing. In England, he was known primarily for his homesickness. He also became only the second man to have been sent off during an FA Cup Final.
Frustratingly for Arsenal fans, his return to Spain saw him claim a La Liga title with Real Madrid. Reyes wrote himself in to history by scoring the crucial goal in Madrid's title triumph.
Davor Suker arrived at Arsenal as the holder of the Golden Boot from the 1998 World Cup in France.
However, opportunities with the Gunners were limited by extreme competition. Despite an impressive goals per game ratio, Suker moved on after just one season in north London.
Arsenal fans were left wondering why Arsene Wenger didn't make more use of one of Europe's most dangerous strikers.
Andrew Cole, or "Andy" as he was known for most of his playing career, made only one league appearance for Arsenal, as a substitute in 1988. Eventually he was sent to second-tier side Bristol City, and that's where his reputation exploded.
Cole was a superb goalscorer, and he quickly moved on to Newcastle and then Manchester United. At United, he won pretty much everything there is to win, including the 1999 treble.
It's frightening to think what he might have achieved at Arsenal alongside Ian Wright.
Who would you have included in your XI? Let us know below.