Ok excellent question, I have many reasons why I play, so I will make a list.
1) I really enjoy poker, I look at it as a sport and I'm very competitive.
2) I love the adrenaline you get when you get a bad beat, or make a ft, or you win with AA vs KK or you win some huge pot, basically you know what I mean I hope.
3) of course I play to win money, in fact I got myself a nice laptop because of poker with my winnings.
4) I got some good friends because I started playing poker, I joined a friendly site CC and met cool people and learned stuff.
5) When I play with my friends and family at home, I enjoy having a good time and spending time together.
6) Poker is a game of skill, not luck like some say.
7) I'm not great at math but I really enjoy the math behind poker, pot odds
and stuff like that.
8) I'm sure there are more but that's all I can think of right now.