Hymen, if you are a snappy dresser and drive a flash car maybe she is seizing you up as a potential boyfriend? Either because she thinks you are rich and / or handsome.

My advice is to talk a lot about your girlfriend (whether you have one or not!) If she doesn't get the message maybe just brush off her questions and hopefully she will stop invading your privacy

I don't agree that you should hit a massage girl just because she is beneath you or gives you back wrong change. Afterall its possible that she gave you the wrong money by mistake.