It was through Steam, so it wasn't a face to face deal, but we'd known each-other about two years, and were friends. I and this friend and another friend had this trio of friends going, wherein we would play games together and generally hang out. We never really discussed typology, but knowing this guy, I believe him to be an INTP with a particularly heavy focus on absentmindedness. The others in the group were an INTJ and an INXP, the latter being myself.
Basically, we'd all known each-other two years, and this friend of mine suddenly withdrew. He severed ties with us hardcore, removing us both from the majority of his friend lists, including multiple MMOs and Steam itself. He left us no explanation for this. Indeed, the only way we even knew about it was a suspicious lack of him being online.
This topic would have gone in the advice or relationships section, except that I am not so much hurt by this behavior as simply confused. Does anyone have any insight into why a long-time friend of the type described would suddenly walk away?