iGNORE and be patience, give a way whenever possible.If someone had heard of one who shot the other because he didnt gave a way after flashing him? I dont want to steal the thread to tell the whole story. but this is a real story happened here in Qatar. The family of the deceased doesnt want to accept the blood money, you give the climax of the story...
I learnt a lesson from this one, so if someone flashes, i just ignore it and find way to give him the way. I learned patience in this scenario, i just ignore the one tailgating, because i want to live for my children...

So please, just ignore and drive calmly as you can...

"There's nothing we can do to change the past, if it teaches  you a lesson profit from it then, forget it."