We're all familiar with the thrill of victory and the agony of defeat. Not only is it a familiar phrase but, unless you've grown up with the world's most protective parents, you've probably experienced both ends of the spectrum a few times yourself.
Literally, competition describes a situation involving two or more parties, the outcome of which results in a winner and a loser. And as the initial quote implies, competitions tend to be emotional, so much so that you might be inclined to ask why competition wasn't included back in the emotion section. There's certainly ample reason to address it there; I've personally seen grown adults do some very emotional and inappropriate things for no reason other than competition.
Yet I think there is a distinction that makes it wise to address competition separately. Without competition, the emotions of games are largely vicarious: the player feels empathy for a protagonist. With competition, the protagonist is the self and the empathy is direct.
In a way, competition is a vehicle for emotion (particularly drama). Once competition enters the picture, many people can't seem to emotionally separate reality and fiction; we project ourselves into the game so completely that there is no longer an emotional distance between participant and game.
And this is what makes competition so powerful. Competition is raw emotion. Anticipation, Anxiety, Fear, and Elation all come bursting out uncontrolled, an emotional rollercoaster that is as exciting as it is unpredictable.
Anything that can be measured can be competitive but once one gets down to categorizing, competition seems to fit into seven broad dimensions:
Physical skill. Competitions of strength, speed and accuracy. Includes sports like baseball or surfing, and reaction-based video games like Pong or Call of Duty.
Creative skill. Competitions of creativity, such as painting, dancing, cooking, directing, writing, etc. The goal is to innovate and please the sensibilities of a group of judges.
Mental tactics. A broad category that includes anything strategic -- that involves reading and predicting the behaviors of a system (including the influences of other players), from Civilization to chess to the play-calling of American football.
Diplomacy. A form of strategy that involves reading and predicting the behaviors of potential allies and acting with the intent of influencing opinions. Often called politics, or popularity, and includes contests from elections to hierarchies to multi-sided war games.
Knowledge. The accumulation and mastery of rules or facts, from highly formalized games like bridge, to straightforward trivia contests. Can also act as an alternate approach to mental tactics -- if the rules of a system can not be deduced, optimal strategies can be observed and memorized.
Time. Competitions of persistence or patience, measured by time and participation. Includes contests of participation such as a radio show call-in, an online social "mafia" game, or a staring contest.
Luck. Anything truly random, including (in many aspects) dice games, card games, sports, gambling, etc. Yet, given structured analysis, statistical odds become predictable and, over multiple trials, luck games will evolve into contests of statistical knowledge.
In many cases, a competition takes the form of some combination of the above seven forms. For example, the game show Wheel of Fortune requires both knowledge and luck, while a Madden football game requires physical skill, mental tactics and knowledge of the opposing team, and StarCraft involves at least a little bit of almost all of the categories (the exception being creativity).
In a true competition, success is measured relative to the performance of the other players. This means that if one player succeeds, another necessarily fails (the metaphorical sum total of their success being zero).
A competition in which everybody wins is not a zero-sum competition. Although if one player is recognized as winning more than the others, the competition could be perceived as being zero-sum (in this case, the performance of the theoretical average player would count as zero). A college course that grades on a strict curve is an example of a zero-sum competition.
The distribution of winners and losers does not need to be symmetrical across the full set of participants to count as zero-sum. For example, in Monopoly, only one player wins while all the others lose, and in credit card roulette, only one player loses while all the others win.