Light switches, lol. Most of the ones around my house are double light switches and I have to have them either all on or all off. Have to check a good 3 or 4 times that the alarms are on all the way around the house before I go to bed or I find it impossible to sleep. Salt and pepper grinders as well, ha! I've got odd shaped ones where the twisty bit doesn't align with the base unless you twist it to match. I can't stand it when the twisty bit and the base aren't aligned, I go nuts