People who don’t understand the use of turn lanes or turn lane adjacent lanes.
Today waited multiple minutes for someone to turn onto an interstate. There was an entrance/exit lane. You had to understand basic acceleration and merging. But no. We sit there like assholes so you can turn across two lanes and then have to floor it anyway. Dipshit.
Piggybacking on this, in Texas we frequently have roads with wide shoulders (maybe most places do, but I'm used to Louisiana, where the roads were built for bicycles and shoulders are the patch of grass between the solid stripe lane edge and the incline into the ditch), and people around here frequently use them when turning. It's technically illegal, though a lot of times it doesn't cause a problem. I know why people do it, they're trying to be nice and help the flow of traffic on the road by getting off of it as they slow to turn, allowing the highway drivers to continue at max speed.
But it causes real problems if everybody doesn't do it the same way, and some people follow the law, while others are technically breaking it. So if I obey the rules and slow down in the highway lane, when I go to turn, I run the risk of turning right into a vehicle that was coming up beside using the shoulder to slow and turn on the same road. Or, if I do the common thing and use the shoulder, I run the risk of running into someone using the proper highway lane. I've been in some near misses, doing it the correct way. Or maybe multiple people in fact do it the same way, but if they both use the shoulder, they might get on the shoulder at different times and that still causes problems.
I admit, I use the shoulder my fair share of the time, particularly when I'm the only one on the road. Or sometimes if I clearly see no one is slowing down or using a blinker. But if traffic is congested or I'm not positive what everyone around me is doing, I drive the way the law dictates, and it peeves me when everyone won't do that. The more people there are, the more everyone needs to follow the rules. Do they do it? No, they just nearly cause accidents and then keep going, seemingly unaware they just broke the law and caused a wreck because of it.