Once I had a client who had to watch every move I made from about 4 ft away. With drill in hand, and client still HOVERING over my shoulder, I yelled "Ooops!! everybody run!!! I think I drilled through the natural gas feed to the kitchen!!!!!" Client ran, tripped over my tool bag, and fell on the floor. The customer failed to realize he had oil heat and an electric stove - no natural gas service................ (and no sense of humor) Oh well, at least he stopped hovering as I was packing up my tools.