Thanks For Nothing

I wish service people in stores where I didn't buy anything wouldn't say "thank you" as I'm walking out the door empty-handed. I'm visiting Cincinnati, and I was in a part of town, the equivalent of which would probably be Lincoln Park. I went into a store where they were selling a bunch of Buddhist themed merchandise. For some reason, yuppies and housewives got really into Buddhism back in the 90s (not enough to actually practice it), and it just sort of stuck. I think it had something to do with that Brad Pitt movie. Anyway I went in looked around and left and as I'm leaving the lady says "thank you!" Thank you for what? I didn't buy anything I just took up space for a brief moment, possibly farted, then left. The only thing I could conclude is she was being sarcastic and as a non-paying customer I don't appreciate that kind of service.