I can't stand the motion sensor hand driers, they are the worst for me. First there is usually an issue of having to hold your hands up high, but also the sensor seems to be located behind where you have to have your hands, so it keeps going off. By the time you have found the one position that works the drier has been running for a while and is producing burning hot air that you don't want to put your hands into. You then dry your hands on your personal stash of paper towels and give it up.

My dad is terrified of motion sensor toilets. He is blind, so he doesn't know it's going to do it as he leans cautiously around to locate some form of flush button and WHOOSH!