I know it sucks, but sometimes you have to just force yourself to be polite and nice. There is one writer at my job who is just the worst writer in existence, and he never follows instructions, and he makes my life 10000x harder, and he doesn't listen to feedback, etc. etc. etc.--and while I WANT to just tell him how terrible he is, I don't, because it's not the best thing to do. (My boss has finally approved a sit-down meeting focused solely on improving his writing, you win by being nice too.)