1) People who don't indicate at roundabouts leaving you guessing if they're going straight on or turning right.
2) Where I live all tractor drivers who drive merrily on doing 30mph in a 60 and ignore the fact that there's 20-30 vehicles behind.
3) Lorry drivers who tailgate another lorry making it impossible for anyone to get past
4)Ditto the above where some old soul is doing 40 in a 60 and everyone else closes up and no-one makes any attempt to overtake or leave a decent gap for others to do so.
There are others but I'll leave it there for now.