What are your top 3 worst driving habits that really get on your tits?

[SphericalRotundities]

here are mine:

1. Twats on mobile phones
2. People who stop at roundabouts when nothing is coming from the right
3. Tailgaters

Come on get it off your chest....

People who wear hats in the car.
I'm not very tolerant.

1. Not Indicating/ Indicating wrong/Breaking before indicating
2. Driving distracted & erratically, on phone/eating etc
3. Tailgating

Scurry - I'm with you 100% on the hat thing - weirdos

People who drive up your arse and give you a hard time for DRIVING AT THE SPEED LIMIT then zoom past and overtake you dangerously because they're so impatient. I hate the fact that people like that are driving around built up areas with kids around. Twats.

People who beep and yell at you for making a lane mistake or being in a tricky situation like trying to park on a busy road, and holding them up for a few seconds. It can happen to anyone. I always try to be nice and friendly to anyone else I see who's in a bit of stress.

Mobile phone users.

Oh and (4) people who rail against speed limits and speed cameras as if they are somehow impinging on their human rights. It's the LAW you idiot and it's for other people's safety...

The trouble with all these tosspots is that they think they are fantastic drivers and that's why the rules shouldn't apply to them. I wish there was some way of really getting through to them and I think there should be more (and better) adverts about bad driving.

Can't limit it to just 3 but, thankfully, lots mentioned already.
40 mph cruisers - yes
Non indicators - yes
Hesitants -yes
Tailgaters - yes
BMW drivers -yes
Manouvre, signal (maybe), mirror - yes
Middle lane hogs - yes

Additions to the list:

Old men who wear a 'bunnet' while driving.

People who won't drive on motorways/roads they don't know. (If you're so scared you should not be driving AT ALL)

People who can see you have 2 kids in your car, yet still park less than 6 inches from the side of you in the supermarket.