He got into a rock fight with a grown man as a little kid.
Growing up in a predominantly white neighborhood in the 1920s meant the Robinson family had to endure unsubtle racism that would make Cartman blush. In one such instance, an little girl ran up to Jackie and dropped three 'N' bombs on him. Jackie came back by calling her a "cracker" and she ran and told her dad. The father confronted him and the two exchanged rock-fire until the girl's mother broke it up. That's right, a grown man had to be convinced by his wife to stop chucking rocks at a little kid. It was a simpler time.