I have severe Car OCD but mainly focussed on cleaning. That said, couple of issues:
1) Hate when you've got the auto wipers on and they are not parked properly when you switch off. I have to make sure they are parked properly.
2) Hate the steering wheel being anything other than centred when parking. I like everything lined up properly.
One of my late uncles had an odd one. He had a Mk2 Jag (Inspector Morse type). Long bonnet. He couldn't bear that to be dirty when looking out the front. He often, if in a rush, just cleaned the bonnet so he had the illusion of a clean car when driving.