We have all the usual morons around here but are a couple that really drive me nuts.
You're tooling along, there is a small but appropriate gap between you and the car in front of you and NO ONE behind you for as far as you can see... and some idiot will pull out right in front of you, causing you to slam on your brakes to avoid hitting them. They could have waited 3 seconds and pulled out after you passed and taken their time but NO!!!! They see a small gap and jump into traffic. Their line of vision extends about to the end of their hood. I was taught to look two, three or five cars ahead, or back. GRRRRR!!!!!!!
Same thing applies when someone makes a left turn across your path, right in front of you, when there is no one behind you for 500 yards. So stupid. Then they get all pissy when you give them the salute and horn.
The only other one I'll menion is fools who use the left turn lane as a passing lane IN A 25 mph SCHOOL ZONE!! and go flying past cross walks of kids then slam on the brakes and make a sharp turn into the elementary shcool parking lot so their own kids won't be late for school. I've seen that happen several times. They would be the first to sue if their own kids got hit by a speeding car on their way to school but it's somehow okay if they put other kids in danger. That takes a special kind of stupid.