Freudian Excuse/Tabletop Games


 * 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."
 * From the Greyhawk setting; Vecna, the most dreaded villain ever to threaten Oerth, God of Evil, and the one who tried to unmake reality itself and remake it in his own vile image, was not born evil. His mother Mazell was among the untouchable caste of the theocratic nation of Fleeth, and the last surviving of the Ur-Fran tribe, which the Fleeth had systematically eradicated. She was a witch who practiced dark magic, including necromancy, certainly no angel - she despised the aristocracy of Fleeth and said her fondest desire was to see the severed heads of every citizen stacked in its marketplace. But then, this may not have been an unreasonable desire. Scrounging out a meager living as a hedge mage, one day a chambermaid came to her, requesting an abortifacient (a magical morning after pill, more or less) for a "friend." In truth, she wanted it for the princess of Fleeth, who had been impregnated by one of her guards while cheating on her betrothed, the Queen having ordered the chambermaid to go to Mazell in order to prevent a scandal. Mazell gave her what she needed, instructing the chambermaid to give the “friend” one pinch of it a day for a month, but the Queen tried to hurry the procedure, tripling the dosage. The princess died from the overdose, and Mazell took the blame for it, captured and publicly executed/ Vecna, however, escaped, his Start of Darkness now inevitable, and upon achieving lichdom, his mother’s fondest desire was granted, in a brutal, bloody campaign of revenge that likely pushed the Master of the Spider Throne past the Moral Event Horizon.
 * Also, his apprentice Acererak, the Big Bad of Tomb of Horrors, had a similar tragic backstory. Short version, a really stupid wizard summoned a balor, a very powerful demon, but was unable to control it. It killed him and then raped a servant girl,  impregnating her. Miraculously, she survived the birth of her half-fiend son, Acererak, and tried to raise him as best she could, but ten years later she was lynched by a mob  who blamed her for bringing this "demon-child" into the world. Doubtlessly, they'd have killed Acererak too, but he was rescued by none other than Vecna himself (still a "regular" lich at that time) who destroyed the town and took Acererak as his protégé. The experience destroyed any hope of salvation for Acererak, not only causing him to develop a hatred of living things, but the concept of life in general, deciding only two years later - at the age of 12 - that his goal would be becoming a lich like his mentor.