Like you, I can't count how many times I've been cut off or nearly blindsided. Traffic being what it is in Doha, I am often stopped near such dunderheads. I make a show of taking a picture of their numberplate and car with my phone.

Most stop with the hand gestures and mouthing off (in their car of course, not to me).

While I've never reported these incidents, I think it's important not to retaliate in kind - get evidence in photos in case it escalates.

My being female makes it easier for me to do so. As I can say I felt threatened or intimidated by a male driver. Also, being a middle aged white western woman works in my favour too.
Signature line > "You can't fix stupid"