Cop pulled me over for staring at him?

Alright, I was driving to the bank the other day and a cop stared talegating me when i was only going 3 over, i didnt care i had cruse control on and maintained. A second later he pes me in the right lane going about 10 over the speed limit, he decided to cut back into my lane and crossed the thick white line (that you arnt supposed to cross) into the newly formed left turn lane. he ended up about 4th in line ( right where he would have been if he didnt do all of that). Anyway, I then decided to glare at him for the breif moment that i went by, as i would do to anyone who drove like that. I ended up being stoped frist at the light going straight, he decided that he would flip on his lights then and pull me over and asked for licence and all the ussual stuff, then he lectured me on why i shouldn't do that. Example : "he could be going to a burglary and be in a hurry". Alright , now to the point. Can he do this? does he have to have a valid reason to pull me over? Should i report him?