1)Even as an amateur I am offended when an idiot with an SLR thinks they're a pro. They need to learn their place, its more for their own good.
2) The bloody cost of everything. After paying for my first L lens, my wallet needs guy-wires to stop it from floating away. I think I've spent around £1200 (only!) on kit now and I've barely even got started. Need to replace my tripod next...its wonky which is another £100-150, plus pay for a shutter overhaul on a Leica which is an open ended cost. I know its not about the kit you have, and more about how you use it, but there is a minimum standard really.
3a) People who constantly go look at me, look at me! When they have little or no talent and are just taking snapshots. I know you need constructive criticism but its useless unless you've actually learnt the basics. Plus you can just read about it...its bloody everywhere, theres plenty of literature teaching you about photography!
3b) The idiots here who just say 'I love your work' or something like that and aimlessly praise rubbish. I'll admit that I'm no pro, or anywhere near the best, but I know my place.
Thank you for asking this question and allowing me to let some steam off.