There is a entry lane onto 94 north of chicago where the speed limit is 70 mph but every single person wants to merge at like 45 mph, but then they will keep on accelerating (slowly) to like 100 mph and pass you. I fucking don't understand.

Also going significantly slower than traffic and changing multiple lanes at once, slowing down far too early for an exit, going very slow in the middle lane so traffic flows around both sides, and some others as well. Basically if the car is going slow enough to be comparable to something stationary in the road it can be a hazard.

But it really does have to be wildly different from traffic, not just 10-15 mph different.