Men vs. women
Quantity vs. quality
"The Man" competition:
Men don't care about what kind of women they get attention from, just as long as they get more than their buddies. One more phone number after a night out is validation to them that they are smart and handsome, worthy of adoration.
The "Woman" Competition.
Women care so much about who they get attention from that they want YOURS because they want to prove they can. It's how they validate their own crushed self esteem. It proves to their shallow and fragile egos that they are 'pretty' on the outside, even if it's counterproductive to the inside.
Don't compete with anyone but yourself. Love isn't a game, a prize or a competition. It's rare and special, and if you don't treat it as such, you'll lose it and end up alone.