A couple things that grind my gears:
Cis people telling me when and how to be offended. It's never on the cis person to decide what's offensive or degrading to the trans person. Example: If I think Dave Chappelle made a transphobic joke, then I think he made a transphobic joke. A few cis people tried to tell me "oh, he wasn't being transphobic." You're not trans; it's not up to you to decide.
"Struggling with pronouns."- I've been Facebook out for over 2 years. I can understand struggling when I first tell you, but if you're still "struggling" two years later... it's not a struggle, it's a deliberate choice. I know with operant conditioning, antecedent - stimulus - behavior - consequence- reinforcement. Then again, the goal of reinforcement is to get you to do it without me handing you a cookie every time you say "she/her."