People who park with their headlights on. Particularly: people who park on the wrong side of the road, facing traffic, with their headlights on.

You know what I can't see in this image? ANYTHING AT ALL BEHIND THE CAR. I can't see if someone has the door open and is exiting the car. I can't see if people are standing around or near it. I can't tell if there's traffic or if the @#$%ing earth just ends suddenly right behind the headlights.
You know what's not remotely safe? NOT BEING ABLE TO SEE WHERE YOU'RE DRIVING.
If you're going to PARK, and not go anywhere, you don't need headlights.
See, cars are equipped from the factory with a variety of lights. Some of those lights are there to make you easier to be seen by others. Some of them are there to enable you to see better. Headlights are in the latter category.
PARK lights. Park lights are designed to make you easier to BE SEEN. If you are PARKING your car and need to be seen, turn your damn HEADLIGHTS off and turn your PARK lights on.

Whoa, would you look at that! I can see the car AND the rest of the universe around it. How incredibly useful!
If you're the kind of d!ck who parks facing traffic (so on the wrong side of the damn road in the first place) and can't spare the .000000003 IQ points required to realize you're blinding EVERYONE, you are scum and I hate you and your children and your dog and your face.
Even if you're not facing traffic...you're facing something. Another parked car, a home, an apartment, somebody who isn't interested in being blinded by your smegging headlights. You are not moving. You do not need to see where you are going because you're NOT GOING. Turn your effing headlights OFF.
Note: sheer coincidence that I found two BMW pictures for this. They were the best photos GIS turned up for headlights and parking lights.

