i have a paternal uncle whom i loathe. when i was a child, say around 5 years old, i allegedly got up in the middle of the night, open his dresser drawer and pissed on all his clean clothes. afterwhich, i went on to piss in all his shoes.
while funny in retrospect, why would a 5 year child have so much contempt for ... anyone? this is learned behavior and our best guess is he did something to me which made me hate him.
Even today, he continues on being a horrible human.