I unfollow friends all the time when they are in a hissy mood. It doesn’t mean anything, I just don’t want their day rubbing off on mine and sometimes unfollow is the easiest way to clear your timeline for a few days. Muting works but then you forget to unmute. With unfollow you still see their notes if others reshare and you don’t forget they exist - I think it’s better than mute. Sometimes we get annoying to other people temporarily (who isn’t guilty of that) and that’s ok too. Other times it just posting too much at once or posting things about an issue people don’t care about - point is it can be any reason without any permanent judgment of that person.