Guess I'll leave my top 3 PPs since I've read everyone else's:

1) People who think they are better than others.
I don't care if people are rich or poor, have a PhD, MD, DO, or their high
school dropouts, etc.
We're all just people and should be treated as such.
2) People with no sense of humor.
If you can't laugh and have fun (at least some of the time) - what's the
point?
3) People who knock others for buying/doing what they like.
Options are great. That's why there are hundreds (or thousands) of
different houses, cars, etc. - so all of us can find something we like.
It would sure be a boring world if we only had one house or one car to
choose from.