i think i explained it elsewhere as feeling like a judgement that's not consistent with my own standards. so both of the examples you give (misuse and rating) are part of that. it's a little like having a label stamped everywhere saying "good" and "bad" that you constantly have to ignore, because it's not your set of values.

obviously the same kind of thing happens in real life, but there conversation is much more fluid, so these signs are transient and negotiable. also, there's not a finite number of rooms in which you can chat to other people - it's easier to adapt the context.

someone else has said how they managed to get over this in the shower. good for them. i got over it by writing a greasemonkey script. generally i find writing a script to be easier than changing my (largely subconscious) cognitive processes, but ymmv.