(Example of mine)
Borderlands I pick Brick because he is experienced with Rocket Launchers and basically blowing [censored] up. This is part of my personality where I determine area splash damage, reflection damage off hard surfaces, and enhanced damage towards enemies. To me there's nothing like blowing something up to see it litter the landscape.
Another play style i'll gravitate towards is the hunter sniper style in games like Crysis. I'm almost constantly using the camouflage system combined with silenced weapons to pick away targets quickly and cleanly. Headshots are always my friend when I play FPS games along with plenty of grenades.