I nominate myself for Idiot Of The Day.
I bought one of those automatic air freshener sprayer things on clearance. The kind you get to set it to spray the aerosol every so many minutes. It had a hole for wall mounting. There was a screw sticking out beside the thermostat, so I hung it there. I go to check the thermostat and it sprayed me in the eyes!
Thankfully it didn't blind me. My face smells like apples and cinnamon now.