Why do girls only want to be friends?

I am friends with a lot of girls and they tell me I'm really good looking (and they love my abs ;) but why do they only want to be friends? I am really nice and I never get on anyones bad side because it is just so much easier to be friends then enemies! I do things 1-on-1 with girls all the time and I help a lot of girls with relationship problems, but it seems I'm destined to be only a friend to every girl I meet and nothing more. I just graduated this year and I hope my luck will turn around in college.