Well, I don't play for score, since having a high score would require time, focus, and doing things I don't feel like doing. I only do that if I'm getting paid, and I'm not going to work all THAT hard even then.
I don't play for fun, since flying around in the AHII MA, trying to maintain the concentration nessecary to watch your back at all times, while trying to maneuever an aircraft around, avoid getting shot in the face, avoid gangbangs, and occasionally hit something, is about as not-fun as you can get this side of the dentist's chair.
I guess I play because I like animals too much to shoot them (except wild hogs! ugly destructive fiends! Like politicians, but with cleaner sexual habits), and shooting people leads to prison terms (Even politicians, unfortunately). So I shoot cartoon airplanes. If I can bring just a little dis-pleasure into someone's life by whacking their cartoon airplane, that gives me a warm inner glow.
Of course, the worst part is that occasionally, when a bandit INSISTS on being difficult and forces me to THINK and tries to wriggle off the hook before I shoot them (most annoying!), giving me much difficulty, the pervs almost act like they enjoy it. Whaddya mean "Salute"? Why the heck did I go to the trouble if they're just going to think I'm a jolly good fellow for blowing their pixel-plane out of the sky? Most vexing.