It's a long story, but the story behind the githzerai and githyanki in Dungeons & Dragons is effectively thus: the Gith were slaves. They rebelled. One faction wanted to conquer the universe so they would never be enslaved again. The other wanted to train all their race to overcome both literal and metaphorical enslavement. On that day they split; one to found monasteries of order in a plane of chaos, and the other to maraud the planes. This example both uses and subverts the trope.
When it gets down to the basics, the entire galaxy-shattering civil war that brought the Imperium of Man down into the nightmare that it is today is the result of one very long, very brutal series of Freudian Excuses.
Recent stuff reveals it was actually a Xanatos Gambit by Lorgar the first heretic who was a little off his rocker from the start that created the current situation.
In Forgotten Realms, Cyric's mother was a failed street performer and prostitute who was murdered by his most likely father after she tried to get him to acknowledge his child. His father then sold baby Cyric to a childless couple looking to adopt for financial reasons. He was ostracized for his background, escalating until his adoptive parents openly rejected him on this basis (and then he killed them). At first, a human and less blatantly evil Cyric tells this to (future) Mystra to explain why he thinks love is nonsense. Hints of its continued effects on him can be seen after he hits godhood, when he exalts his mother in the Cyrinishad as a "beautiful bard with a mind as quick as Oghma's."
