"One could come up with a story about how people are motivated to act selfishly but enjoy acting morally..."
Actually, I think a lot of stories are like that.
Because "CONFLICT IS DRAMA!!!!!1!!!one!!!!", a whole lot of stories I've been reading involve the characters having an arc that goes like this:
-Problem occurs, everyone has different ideas about how to solve it.
-Ignored dissenting character, perhaps with prodding by certain outside forces, blows up, acts like a jerk, and storms off.
-Dissenting character realizes that regardless of how much better their own plan was, that they've let a lot of relatively small and meaningless things drive a wedge between themselves and their friends, right when their friends needed them to be there and "Oh I was a fool!" and blah blah blah kiss and make up, Friendship is Magic.
Unless its a zombie apocolypse story, in which case the character in question NEVER stop fighting until they die, or at least they stop and reveal "they were a good person all along who made bad decisions" about ten mintues or so before the zombies eat them.
AND I APPARENTLY DOOMED MY DESCENDANTS WITH ORIGINAL SIN, TOO! WILL THE CONSEQUENCES OF MY ACTIONS OF A SINGLE AFTERNOON NEVER END!?