I used to make jokes about being unable to perform a specific task after receiving an injury to one of my joints, but then I stopped.
And the internet was a better place for it.
As for threads that I hate, I'd have to say pretty much any thread that intentionally seeks to start a flame war by bringing up a topic that's highly controversial without specific context to limit the discussion to a narrower subtopic. For example, a thread that says "religion sux lol" deserves to die a slow and painful death, but one that asks a question about how followers of a faith can have a holy text that prohibits/limits violence but those same followers can kill in the name of their faith seemingly without remorse is worth some consideration.
That's probably not the best example, but I think you get my drift.