douche

Some guy who thinks you're his buddy, bro, or pal while patting you on the back when he leaves you, a douche that just walks a way giving you this unexpected pat, though you never talked to him and don't know whether you should have said a word with him before he left or not, hmm what to do situations, situations...

I'm not your buddy ya lame douche, go take the stairs, and stop loitering the elevator.. and floor five.