What grinds my gears?

This thread is where you tell us what grinds your gears (What angers or annoys you)? To start it off what grinds my gears is those brainless idiotic teens that talk loudly in public places and just always swearing "Fuck this" "Fuck that" on and on. I have no idea what they are on about but I'm quite sure they are talking about teachers at their school or their parents . I just cannot understand why they would hate their parents.

I just shocks me how dumb, ungrateful to anyone except mates, some of today's teens can be.

Smokers are the stupidest people in the world. Whenever I am near a smoker I cough constantly to let them know they are making other sick.