Our competitive drive has been ground into our consciousness as a species; it's part of our evolution. We naturally want to do better than other people because our subconscious mind tells us we will have a better chance of survival. We see this everywhere: Advertisements tell us a product will make us better than our peers; we hold competitions like the Olympics to find the best in the world; and we strive to become the best in every way.
The roots of our competitive drive come from prehistoric times. Professor Bernd Heinrich of the University of Vermont (an expert on the human competitive spirit) speaks in his book Why We Run: A Natural History of "our primal, indomitable drive for perfection." As part of our species' evolutionary process, we were forced by natural circumstances to strive to achieve more than our neighbors, because if you didn't your neighbors would eat all of your food. We were pressured in every way - for food, for mates, and for safe places to sleep and live.
Although in the modern day we no longer run the risk of starvation and death unless we're in the depths of a serious World of Warcraft addiction, the competition for resources is still present in our competition for mates and jobs. At work, we chain ourselves to computers to earn promotions and better pay - resource competition redirected into the modern setting. And the success of dating websites shows that we still put in a ton of effort to find mates. Whether or not match.com is the best way of doing this is another matter, but I guess it's better than marrying one of your father's rich business partners.