One very bad idea is for an optician to display rimless glasses on a glass shelf.
When a customer takes off her own glasses it makes seeing the above difficult.
It is easy however, to pick up the large hand mirror and accidentally bash the invisible shelf quite smartly....
It is then advisable for the shortsighted customer to stand very still while the receptionist picks up all the rimless glasses and tries to find the ones the customer was wearing when she came in.....☺
listen to a man who insists on carving the joint of lamb. especially when he insists on doing it at the dining table in a room which has just been decorated with very expensive wall paper. especially when at the end he waves the carving knife and fork around and spatters the wallpaper with grease.