Why did Percy always hate Del so much?

I guess that all of those things contributed to his 'hatred' for Del. But he was just a pathetic little man with some serious issues. What he did to Del was so very cruel and inexcusable imo.

Yes, it is odd. It was plus of a case of having power and being a bully/show who's boss. Del was evidently weak, and Percy saw this from the very moment he got off the van. Bullies like Percy like having an excuse to practise their brutalities upon. In Del's case, it was the incident involving him accidently touching percy's groin. Percy knew it was an accident, and also knew Del was weak, hence his abusive manner towards Del. Del was also really insecure, cried a lot, and seemed soft - Percy took pleasure in his pain and liked to exploit it, he just got a kick out of mean activites.

The sabotaged execution I think was always in Percy's head ever since he asked the executioner about the sponge prior to Bitterbuck's. He visibly got excited about the thought of what might happen if something went wrong. I think also it was mostly because Del laughed at him when he pissed his pants, but he might have deliberately sabotaged it as he was a mean and cruel scumbag anyway. We'll never know I guess! RIP Michael Jeter/Del.