Before I begin, let me be clear, I'm using the term "OCD" in a colloquial, not a medical, sense.
Anyways, so I have some habits that are a bit OCD. As an example, I cannot leave my house or my car without physically touching my keys. I have to have them in my hands before I close the door. It isn't enough to know they are in my pocket, or to feel them in my pocket against my leg, I have to actually touch them.
This is actually the result of locking myself out of my car, with my phone in the car, at an interstate rest stop.
I also cannot leave a hotel room, without double checking my wallet for my key cards.
I have to have my phone, wallet, and keys in specific pockets, or I freak out. It's bad. Like sometimes I'll put them in my jacket pocket and then feel anxious later because they aren't in my left pants pocket.
Despite living alone, and despite there being no way to view into my bathroom from the outside, I must close the door to take a crap. Anything else, the door stays open. But for that one bodily function, the door must be closed.
I also close the door when I shower, but that's generally to contain the humidity, so there's a reason for it.
So what things are you OCD about?