This thrift store makes me feel like im a "bad person"?

I love to thrift shop but this store Iv been going to always makes me a little upset. The employees constantly ask me if im finding everything alright, many of them all go over to the dressing room area right before I wheel my cart over their to try stuff on. They check all the fitting rooms before I go inside, they had me and friend sigh some papers one day when I was returning something....my friend wasnt even returning anything. We had to put down ou phone numbers as well. Lately it seems like everytime I walk in their somebody on the PA (public annoucement intercom) calls out for SO & SO to report to the OSB room. IM NOT A SHOPLIFTER but I feel like im constantly being watched. I wouldnt mind so much if I wasnt being watching when looking at the bra's (male employees) I love to shop their but this is getting out of hand. What does OSB mean?