What trait instantly makes you despise a person beyond belief?

Pretty much any trait that awful people usually have. I feel these kind of people are pretty easy to spot usually.

Lacking basic manners, can't be bother to do small things that can help others, greedy to a point that hurts other and is OK with that, only looks at people as tools/resources, only argues to win instead of to teach/learn, and the list goes on forever.

It becomes a lot harder to despise people if they don't have any of the usual awful person traits.

I do hate it when people ask to ask though, that always annoys me to no end. Just tell me what you need help with lol