Let me vent and then help make a list of the things that drive enthusiasts nuts.
I can handle being cut up in traffic. I was a White Van Man in London before the congestion charge was a glint in Ken Livingstone's testicles, and long enough to take on a zen-like tranquility over it. I'm honestly not even bothered by people that nearly hit me jumping a red light.
What bothers me is the small but insane and unsafe things. People that don't get up to speed on a slip road to join the freeway or dual carriageway is a big one. But what really gets me, and now I live in the United States Of Trumpingrad, is people that wave other people across four-way stops when they clearly pulled up first. It's ridiculous and I've seen two actual accidents from it and several near misses over the past year by somebody disrupting the order of flow because the system isn't good enough for them.
For non-Americans, a four-way stop is a simple system, much like the traditional British roundabout, except you have to stop completely before moving through. The person that stops first goes first, and everyone else goes in the order they arrived. If two cars stop at the same time, the person on the left gives way to the right. You have to do a little thinking, but...
Wait. No, I was wrong. It's not like a traditional British roundabout because it's over-complicated and stupid. A roundabout is simple. You look one way, and if nothing is coming then you just go and if something is coming then you put your foot down and hope you make it. However, for the four-way stop then you just learn it works and it does actually work. It's clunky and annoying, but it does work.
Except when some dumbass decides that the system isn't good enough and decides to be polite and wave someone across in their place. Everyone's head-math goes out the window and the car being invited to go thinks they shouldn't, but the polite person is waving and now time is marching on and someone needs to go, so they do. At the exact same time someone else has pulled up, decided there's to much dicking around going on, and goes as well. Now, two people have nearly hit each other and, of course, neither are the person causing the damn bloody incident.
Anyway, I've got that out of my system and I want to know what gets on your goat and pulls the horns. If enough people are happy to share, then I'll compile a top ten based on the narrow and skewed demographic that is car and driving enthusiasts.