"Everything must be random! Random stats, random hp, random dungeons, random encounters, random loot." There's a place for random stuff, but don't overdo it.
On a related note, "Balance doesn't matter! Pick the options that fit your character, even if another option is inarguably superior!" I'm far from a hardcore power gamer, but I just can't ignore math.
Also, "My character is the strong silent type" and "I brought a non-adventurer to D&D." Seriously, I've had PCs wander off into the sunset to go back home. Because that was their character goal.
A table where a fight almost never happens. And when it does, it is hand-waved because half the players and the dungeon master do not know or care about the combat rules. Bored now!
Luckily I've never experienced this, but yeah I couldn't handle this style. I might even feel justified in using that horribly prosaic phrase "It doesn't feel like D&D." I think rolling d20s to kill monsters is one of the very few things that count as a D&D fundamental. And I like it that way.
Others include "Everything should be 100% by the book" rules-lawyers, and worse "Everything should be 100% realistic" reality-lawyers.
Yes, and yes! In fact I have a slang word for gamers preoccupied with RAW that I won't post in public, no matter how tempting it is. It burns to keep it inside though...
PC Plot Protection. The game revolves around the PC but the world does not. PCs should not be treated like special snowflakes. I don't care how powerful you are mouthing off to the king of the land is a bad idea and there will always be bigger fish.
God yes! Nothing kills excitement and tension like knowing my PC can't die.
I can't game in a large loud room (like at some conventions or game stores) where I have to yell to be heard.
Does that count?
Hell yeah. Also, "You don't mind if I smoke/drink, do you?" Well I'm asmatic and I don't think you're going to be nearly as funny drunk as you think you are, so YES I mind.