I usually try my best not to overhear what others are saying. My mind is already a very cluttered and violent place, i don't need retarded input from no one.
I also usually don't stare at people or if i see something that would cause others to stare, i make the point not to.
I have found behaving this way maintains my sanity somewhat.
...but yeah, the most disgusting thing i despise is fatso's who are obnoxious, vocal, and judgemental.