A typical example here might be something like chess. The primary reason people play it is competition and enjoyment of the game. But there are some who a distorted mentality and simply want to win, even if they're not the one's doing anything, and so you get things like people using computers to cheat. And online chess sites (and increasingly even major over the board events) only work so well by making sure that these sort of people are completely removed from the game.

The desire to compete is somehow not really the same as the desire to win. This is overtly apparent in things like body building. 99.9% of body builders will never compete in a body building show, let alone win, but enjoy the journey that's mostly full of years of self inflicted pain, occasional injury, and endless dedication - largely for the sake of competition and of course what it does to your body. And that latter part isn't really about showing off or sex or whatever, but simply about pride in what you've accomplished - much in the same way one might take pride in their ability to play chess well, or manage a healthy business.