Rude people
Self-important people
Bad drivers
Cyclists who think they do not need to follow the rules of the road
Hypocrites
Mean people
Judgemental people (they are usually also hypocrites, AND mean!)
People who think they're experts in everything
Doctors who don't listen
Ingrates, boorish careless types
People who know you need help but remain aloof anyway
Anyone who engages in any kind of cruelty
Anyone who leaves a mess for someone else to clean up
Thoughtless neighbours (I've been there many a time)
Passive-Aggressive people (I had two relatives, and a sister-in-law, who are like this)
Anyone who engages in emotional abuse of any kind (bullies, haters, schemers, liars, etc.)
The Willfully Ignorant
The Completely Insensitive (seems to be very fashionable, these days, unfortunately)

...I'll probably think up more, later...