Financial times quoting Robert Downey's character Lazarus from Tropic Thunder:
"Check it out. Dustin Hoffman, Rain Man, look retarded, act retarded, not retarded. Counted toothpicks, cheated cards. Autistic, sho’. Not retarded. You know Tom Hanks, Forrest Gump. Slow, yes. Retarded, maybe. Braces on his legs. But he charmed the pants off Nixon and he won a ping-pong competition. That ain’t retarded. He was a’ goddamn war hero. You know any retarded war heroes? You went full retard, man. Never go full retard. You don’t buy that? Ask Sean Penn, 2001, I Am Sam. Remember? Went full retard, went home empty-handed."
This is the best timeline.
