A girl I know got screamed at for not opening the mustard she served. She works in a relatively posh place, and the mustard comes in this little individual glass pot (I think Colman's or whatever). She hadn't opened the mustard for them and was yelled at. "I work for (local paper) they will be hearing about this! I've never been so offended! Disgusting behaviour."
She just stood there aghast and like "did you want me to open the mustard… now?"