- overpriced food/drink: most of it's literally the exact same crap you can get anywhere else, but for cheaper. Which is why you be sure to bring with you a large purse or murse so that you can smuggle anything from a few pieces of candy to a 3-course meal in there
- children/babies: children wouldn't be so bad if they went to movies they could handle watching or if they were well-mannered enough to be in a movie theater quietly watching a movie in the first place. But too many times neither are the case. and infants... seriously, no.
- verbal diarrhea: I'd rather they text. It's still rude, but it's less distracting than nonstop talking and it's a more contained problem as far as wasted money is concerned
- people coming and going nonstop
- strangers who come to sit beside me when there are a shit ton of available seats everywhere else. I'm no dude, but I'm pretty sure the unspoken urinal rule would apply very nicely here
- fights: nobody wants or cares to hear people yell about why their friend is now a(n) [insert cuss-word insult here]. Nor do they want to be disturbed by them throwing their overpriced food and beverages at each other, let alone be the poor soul who ends up in the crossfire
... just about everything else has been covered in the above replies