Personally I can`t stand the customer looking over my shoulder, mainly because I find it scary! I had one woman turn off the t.v. & literally stand behind me in the kitchen whilst I removed & refitted her boiler! Staring, she was...just....staring....I had the good sense to remove all cutlery & sharp objects from the immediate vicinity though..In the end (about 6.30) I asked her quite politely if she didn`t have anything better to do, whereupon she swiftly made an exit & fell asleep on the couch...staring she was.....just.....staring...