Why would this guy say this lol?

So I was walkin into this halloween store and this dude that worked there held the door open and I was like "thanks" and he said "thank yourself". whyy? why? LOL then we went in there and it was really shady n my bro said he smelled marijuana. xD lmfao idk why i'm telling you this i'm tired and terbrained here have a cat.