My personal answer is that I am a hero, not a villain.
I play redside to be completionist, but I feel bad about it.
I'm the type of girl who would find a 100 dollar bill on the sidewalk and turn it in to the police. Volunteering, passing up contest entries for things someone else might need more, losing sleep on worknights to help friends and strangers who need someone to talk to.
I live my life literally, by the codes of Superman, The Green Lantern Corps, and Starfleet. (Note: This does drive my slightly less Paladin-style wife nuts on occasions, like when I help tidy store shelves or return carts for people, pick up tabs for strangers in trouble at the grocery store, donate all my change, etc).
As I once saw posted...
"Why do people play good guys in no-consequence games?"
"Because my ultimate power fantasy is being able to help everyone."