Having a rival is one thing, having a heated rival who you hate with all of your fiber is another.
For both athletes and fans certain rivalries bring out the best and the worst in everybody involved.
These are the rivalries that have caused fights on the field and even riots in the stands, because of the passion they bring about.
With the exception of number one, which deserves a category in-and-of itself the rivalries are listed in no specific order.
You can not understand the Canadiens/Maple Leafs rivalry without understanding the realities of politics in Canada.
Canada is almost two separate nations with Quebec having their own language and heritage, and the city of Toronto representing everything they hate about the Anglophile nature of the other eastern provinces.
These same feelings have carried over to the ice.
Toronto and Montreal are both "original six" members of the NHL and have been battling each other since 1917.
While the rivalry has been heated for nearly a century, it reached it's zenith in the 1960's a decade where in all but one season the Stanley Cup championship resided in either Toronto (four titles) or Montreal (five titles).
During the late 1970's the rivalry cooled a bit during NHL expansion and realignment (and the Maple Leaf's not having won the Cup since 1967). However, with both clubs now in the Northeast Division the rivalry has received new life.
For an entire decade no fans dealt with more futility than those of the Los Angeles Lakers.
Between 1959 and 1969 the Lakers played the Celtics in the NBA Finals seven times, and lost all seven.
These were not bad Lakers teams either with stars like Jerry West, Elgin Baylor, Frank Selvy, and later Wilt Chamberlain try as they might the Lakers could never beat the Celtics.
However, as good as the Lakers were the Celtics were always better. When the Celtics lost a key player they simply replaced them with somebody of equal talent (e.g. John Havlicheck for Frank Ramsay), yet the constant was always Bill Russell.
Russell owned the Lakers as a player and in 1969 as a player-coach when he told his team before game seven of the finals "A lot of things can happen, but the Lakers can not beat us. They just can't beat us."
Throughout the 1970's the Lakers remained strong winning five division titles, but the Celtics fell into a tailspin after claiming the 1976 title from Phoenix.
However, in the early 1980's the rivalry was given new life as two players stepped on the scene who would "save" professional basketball.
In 1978 the Celtics drafted Indiana State forward Larry Bird and in 1979 the Lakers drafted Michigan State's Ervin "Magic" Johnson.
Over the next decade each team seemed to take the personality of their best player with the Celtics viewed as the gritty, blue-color, hard working (and white) embodiment of Boston.
The Lakers took on the persona of the man named Magic becoming the running, gunning, Showtime, jet set (and black) embodiment of Los Angeles.
During the 1980's the Lakers (5 titles) and Celtics (3 titles) won 8-of-the-10 Championships decided during that decade, one or both appeared in every NBA Finals that decade, and three times faced each other in the Finals.
1984 brought back bad memories for Lakers fans, as the Celtics once again took the titles in a game seven at Boston Garden's where the temperature reached 91 degrees.
The Lakers would finally one-up their Beantown counterparts in 1985 and 1987 both by 4-2 margins.
The 1990's were not kind to the Celtics after a string of bad luck (primarily the deaths of Len Bias and Reggie Lewis) and the disaster of the Rick Pitino era sent the NBA's most storied franchise into sub-mediocrity.
At the same time the Lakers under former Bull's coach Phil Jackson claimed three straight NBA titles behind the dynamic duo of Kobe Bryant and Shaquille O'Neal.
However, the two teams once again find themselves on top of the NBA with a rebuilt Celtics featuring Kevin Garnett, Paul Pierce, Ray Allen and Rajon Rondo beating Bryant's Lakers 4-2 in the 2008 Finals.
The NFL's most heated rivalry had it's beginnings before one of the teams even existed,
In 1958 Texas oil tycoon Clint Muchison attempted to buy the Washington Redskins from owner George Marshall, until at the eleventh hour Marshall reneged on the deal.
Two years later the Cowboys were born as an expansion team owned by Muchison and coached by a former Giants assistant named Tom Landry who didn't think too highly of his D.C counterparts.
The rivalry began to pick up steam in the mid-60's as the surging Cowboys lead by popular Texas native Don Merideth and the Redskins by All-Pro Sonny Jurgenson.
By the 1970's both teams found themselves in the NFC East where legendary coaches Tom Landry and George Allen led their charges in games that almost always decided the division winner.
Since then the rivalry has more memorable games to remember from the 1983 NFC Championship game were Dexter Manley knocked out Danny White, Landry's last game in 1988 when his Cowboy's upset the 'Skins and knocked them out of the playoffs, and the 1998 game where the Redskins erased a 21 point deficit in the fourth quarter to win.
One of the longest standing rivalries in professional sports the Dodgers and Giants have always had an animosity born out of geography.
Beginning nearly a century ago in New York City where the Giants were the team of Manhattan and the Dodgers represented blue color Brooklyn.
However, the rivalry became heated when Dodger's flamboyant manager Leo Derocher took the job as manager of their Manhattan rivals.
Then there was Bobby Thomson's shot heard around the world in 1951, a game Giants fans remember as one of their greatest triumph's and Dodgers fans remember for Derocher stealing signs.
After the clubs mutual move to the west coast the rivalry continued manifesting itself with Giant's pitcher Juan Marichel attacking Dodger's catcher Johnny Roseboro with a bat (pictured above).
In resent years the rivalry has lost some of it's heat, but make no mistake the Dodgers and Giants are still the premier National League rivalry.
Major League baseball's premier rivalry that invokes such passion from as a widely diverse group as author Stephen King, rockers Dropkick Murphys, Billy Crystal and T.V foodie Anthony Bourdain.
The Yankees baseball's gold standard with their 26 World Series crowns, and the long suffering yet ever faithful Red Sox Nation which has endured Slaughter scoring from first, Conigliaro's beaming, the triumph and pain of 1975, Bucky "f-ing" Dent and of course Bill Buckner.
Then there is the name that dare not be spoken in New England, Henry Frazee.
Before 1919 the Red Sox had five World Championships while the Yankees had none.
It was Frazee who sold a promising young Red Sox pitcher named Babe Ruth to the Yankees bringing about an 85-year period where the Yankees would win 26 World Series and the Red Sox none.
The "Curse of the Bambino" would become the line of demarcation where the Sox would become the long suffering losers, and the Yankees the kings of baseball.
In 2004 the curse was lifted and the Sox won the series again in 2007 exchanging the horrors of Dent and Buckner for the memories of Curt's bloody sock and Pedro's take down of Zimmer.
There was a time when Army-Navy was the premier rivalry in college football.
While those days are long passed the rivalry still has tremendous importance to American sports fans, after all what other game between two irrelevant teams brings about this nationwide interest.
The rivalry brings about this much interest because as a nation it is our rivalry. Two teams filled with players that in many cases would be lucky to start on a good Bowl Championship Subdivision team, yet these same young men will one day be defending our country as sailors, soldiers, and Marines.
While the days of Davis, Blanchard, Staubauch, and McCallum are long gone, the rivalry still draws over 60,000 fans a contest and fans still watch.
After all in what other rivalry game to the winning and losing team stand together for the other's fight song, as a show of mutual respect.
Rivals for the day, but potential comrades on the battle field in the future.
I have a neighbor who swears to this day when he has kids the first words they will utter will not be mommy or daddy but rather "Michigan Sucks."
Unlike many of the in-state college rivalries on this list, the Woolverines and Buckeyes are a rivalry born out of pure competition.
More often that not this border war decides who wins the Big 10 Conference and gets a trip to Pasadena.
Doing battle since 1922 the two schools have had many memorable games including the infamous "Snow Bowl" played in a blizzard in 1950, the 1995 "Michigan's nothing" upset, Charles Woodson's epic performance in 1997, and the Buckeye's 2006 victory in a game where both teams were undefeated and ranked 1 and 2 in the nation.
However, the rivalry gained national attention in the 1970's when Ohio State's legendary coach Woody Hayes and Michigan's counterpart Bo Shembeckler led their teams to into what is known by fans of both schools as the "Ten Year War."
Much like Louisville and Kentucky in basketball the Alabama-Auburn football rivalry is for bragging rights in the football mad state where there are no other sports distractions.
The Iron Bowl has roots as far back as 1893 when the two schools first met, yet was suspended in 1907 due to tension between the two schools.
Reinstated in 1948 the two schools agreed to play again at a neutral site in Birmingham so that neither would have an unfair home field advantage.
Auburn dominated the renewed series until 1959 when Alabama hired a young coach from Texas A&M named Paul Bryant and won 19 of the next 25 contests. Since Bryant's retirement Auburn holds the series edge 15-11.
Legendary games in this series are given mythical importance from Kenny Stabler's "run in the mud," to 1972's "Punt 'Bama Punt" game where Auburn blocked two punts in the final six minutes to knock off the top ranked Tide, no college football rivalry is as heated or has as much statewide fan passion.
No college basketball rivalry captures the attention of the nation more than Duke and Carolina, however that wasn't always the case.
For years the two schools separated by less than 10 miles had a one sided rivalry with the Blue Devils being the Tar Heels whipping boy for decades.
Enter Mike Krzyzewski.
Duke had some quality teams before Coach K arrived in Durham (they made the Final Four in 1966 and 1978), but the program was never as consistently good as their Chapel Hill neighbors.
The names associated with the modern rivalry alone scream college basketball excellence Jordan, Perkins, Dougherty, Hurley, Laettner, Hill, Wallace, Stackhouse, Carter, Brand, Battier, Duhon, May, McCants, Reddick, and Hansbrough.
The only drawback might be that the teams meet 2-3 times every season, however each game usually has major implications not only in the ACC but nationally as well.
No college basketball rivalry means as much to the people in it's respective state as when the Cardinals and the Wildcats meet on the hardwood.
There are no professional sports in Kentucky and no other major Division 1 universities to divide the fanbase further. From birth you are either a Wildcat or a Cardinal and there are no other options.
Also unlike the Duke-Carolina rivalry there are no second chances, it's one game per year with the winner holding bragging rights over an entire state for the next year.
For decades the University of Kentucky refused to play Louisville (or any other Kentucky based schools) until 1983 when the teams met in the Mideast Regional Finals in a game known as "The Dream Game" where Louisville triumphed in overtime 80-68.
The rivalry gained added strength in 2001 when former Kentucky coaching legend Rick Pitino returned to the coaching scene at Louisville, much to the ire of the Big Blue Nation.
With Kentucky's hire of old Pitino rival John Calipari, the heat between these two top ten all-time programs looks to remain strong for years to come.
When millions of American's sit down to watch a televised chess match, you know you have a rivalry on your hands.
In 1972 a young American named Bobby Fischer defeated the Soviet grandmaster Borris Spassky with two entire nation's watching.
Much of the Cold War was played out in the sporting arena with two different perspectives taking hold of the world's two biggest superpowers.
To the Soviet's the American culture was a bastion of greed, selfishness, and ego-driven individualism, while the Communist system fostered unity and discipline.
For American's the Soviet system was corrupt and evil, as evidenced by the sham amateurism of their top athletes, most of which were high ranking military officers with no military duties outside of sports.
The suspicions of every American were realized in 1972 when the Soviets were gifted a gold medal in basketball after given not one, not two, but three chances to win the game in the final seconds.
Every Soviet's worse fears were realized in 1980 when a U.S Olympic hockey team with far less talent, but much more team unity and cohesion pulled off the greatest upset in sports history.
The Seoul and Calgary Olympics of 1988 were the last for the CCCP and USA to play out this cold war drama, but the hatred the two nation's shared is still remembered by all who lived through it.
The rivalry between Glasgow soccer teams Celtic and Rangers isn't just the most heated sports rivalry in soccer, but it's the most heated rivalry in the world. Period.
Carolina fans don't hate Duke because it's a Methodist school; there are no ethnic or religious overtones to the Cowboys-Redskins rivalry, the Iron Bowl has never ended in a fan brawl, and the Louisville-Kentucky basketball game doesn't have political meaning dating back to Oliver Cromwell in the 17th century.
The Old Firm has all of that and more, and literally volumes have been written about the rivalry.
Celtic fans will tell you that Rangers' supporters are intolerant, Protestant, Unionists who wish they were English and sing "God Save the Queen" while drinking their afternoon tea and flying the Union Jack.
Rangers fans will tell you that Celtic supporters are dirty, Irish-Catholic, Republicans, who are ashamed to be British and sing odes to terrorist turned martyr Bobby Sands while getting drunk in some Glasgow pub because none of them can hold a job.
Yes it's that nasty.
Add to that tension the fact that in Scottish soccer over the past two decades only two teams have claimed every Scottish Premier League title, Celtic and Rangers.
The Glasgow Derby (or "home-and-home series" for us Yanks) determines not only a deeper socio-political and even religious reality but a deeper reality found in the standings.
Sweep both games in the Derby and you are almost guaranteed a cakewalk to the championship.
While both sides in recent years have sought to quiet some of the sectarian leanings of their respective supporters, the feelings between the Irish-Catholic Celtic fans and the British-Protestant Rangers fans are still alive and well although not nearly spoken as loud.