I'm going to jump on Dead0man's bandwagon here. It's bothersome, but not because you don't like chain pizza. If we got upset every time someone doesn't like something we like then we'd always be fretting. Dead0man, for example, claims not to like mushrooms. Now, I could get my panties in a tight little wad about that if I wanted. I eat a mushroom almost every day. Sometimes several types of mushrooms. Bracket fungi as well. Right now, in my refrigerator, I have two kinds of mushroom and at least one type of bracket fungi. (And those are just the ones we bought. With a magnifying glass, I could probably identify a few more types that I'm getting for free!) And that's just today. Some days we have five or more types of mushrooms. So to see his post in the mushroom thread about being too good, or too delicate, to eat mushrooms was a bit jolting. But I get that. Some folks just don't like mushrooms. Even for a facultative fungivore like myself, the incapacity to appreciate nature's most perfect food is understandable. Bottom line: each to his own tastes.
The bothersome point here isn't one's incapacity to like something, or even one's feigned incapacity. It is the illogic. The question said what is your favorite pizza chain? Now, we could quibble about the choices offered. I did, in fact. (What the hell is Pizza Pro?! And Hungry Howie's?) But the question itself is legit: "What is your favorite Pizza Chain?"
Of course it freaking makes the assumption that you can identify a pizza chain you like. Such threads always make such assumptions. Yes, sometimes the OP finds the need to preface it with "Republicans only" or "Germans only" or whatever, but the absence of "People who can identify a Pizza chain that is their favorite only" as a preface shouldn't lead you to believe that the generally-implied tacit presumptions don't exist.
I also understand that threadshitting can be cathartic. Of course, I take a big, gut-wrenching, bowl-staining dump on threads from time to time. I used to try to always be the first to resort to Godwin's Law, for example, and I went through a mullet period as well. I especially like picking apart some obscure point of grammar which ends up totally derailing what would otherwise be a good question.
In the What's Your Favorite My Little Pony thread that no doubt existed at some point I'm sure there were people dropping in just to make fun of the weirdos participating in the thread. Threadsh**tting.
Oh yeah, I took a huge shit on that thread. I even got flak from some of the more moderate moderators regarding my intolerable behavior in that one. Can't remember how many death points I got, but I'm sure that it was worth it. Sometimes I just get in a strange mood that causes me to want to spread my special blend of wisdom, bigotry, prudery, and alcohol-induced stupor on every thread I encounter, but at least I'm honest with myself about it. If someone has the presence of mind to call me out on it, I promptly admit that I'm threadshitting and move on, rather than trying to make some asinine argument based on false logic and end up digging my hole deeper. Never dig the hole deeper, Avaroës Nix. If you're going to take a big shit on someone's thread, better to leave it in a very shallow hole so that it can be smelt by all.