On at least two occasions some advanced MO users included in their comments phrases which were less than polite. I hope that these are isolated instances or else I would quietly and simply leave MO without a word. I don't know if these are cases of autism or because their English is poorer than mine (I doubt it--my own English is poor enough).

If people would leave MO because they value politeness above MO imperfect manners than whom are the advanced users going to pester? :-)