One time in Victoria's Secret the employees were giving me looks and following me around. I didn't know why until I had already purchased my items and was walking out and they asked me "Are you going to pay for that?"
I had tossed a bag (one of those that they give you to hold items) over the same shoulder as my purse and it had just a single shirt in it- the one thing I hadn't bought. I just completely forgot it was there because I thought the strap was my purse strap. I don't know.
I felt like an idiot and apologized but I don't think they believed me, I think they really thought I was trying to steal by just walking out with the bag.