I wanted to add a light switch to my kitchen. I just felt it made sense to have one in the location. The electrician came out, told him what I wanted. He says "you know we wired a bunch of these houses and I remember doing this one" because it was one of the first.

I show him where I want the switch and I could see his mind melt away. He rubs the wall a few times, stands in silence for 20-30 secs, turns to me and says..."I swear I put a box there. Why wouldn't there be a switch there? It just makes sense there should a switch there and I'm certain I put a box there". I ruined his day.