My OCD goes completely bat-shit when I'm getting ready to leave for work in the morning, something like this...
coffee maker off and unplugged
stove off
computer off
computer monitor off
computer peripherals off (all on one power strip)
sliding-glass door to balcony closed and locked
closet light off
closet door closed
bathroom light off
bathroom door closed (after making sure electric shaver and toothbrush properly on their chargers)
a/c thermostat set appropriately
cats' water bowls filled
air purifiers not making unusual noises
a visual on all three cats, to make sure I didn't accidentally shut one in the closet or something like that
no other mischief for the cats to get into while I'm gone
out front door
front door locked and checked several (preferably a multiple of five) times
nothing under car tires where it will get backed over
no stray cats under the car
In Florida, we've got air-plants, which grow in high places like on trees and power lines, getting all their nutrients and moisture from the air. If I walk past one that has fallen onto the pavement, I've got the urge to pick it up or kick it onto dirt or up into a hedge.
Once I'm in the car and on the way to work, that mess is over with and I can think normally again. (Driving would be a real bitch and possibly quite dangerous if I was still in heavy OCD mode.)