When I do something like that (I'm sure I have left my purse the cart while I walked down the aisle at some point in my life), MY peeve is when people chide me about it. My thought is, "what's it to you?" Sweetana's case is a little different because it's her MIL and she's looking out for her, but for a stranger to comment on something I have no problem with, I think to myself, MYOB.