Something I am OCD about, eh?
That would be sweeping. I run the broom across my kitchen floor at least three times a day (morning, night, and sometime in between). In fact, I actually never put the broom away because I use it so frequently.
I dread the first snowfall/ice storm of winter (and subsequent ones to boot), because after that event (and the salt/sand trucks that come after that), I am sweeping, sweeping, sweeping grit all the time.
And here's the thing. I know I'm never going to be able to sweep up every single little speck. I know I'm going to pad across my floor every day and feel the grittiness underneath. I know there's really nothing I can do about it. Except sweep. I guess that makes me feel like I'm doing something in the battle against ground dirt.
I don't know where this obsession to sweep comes from. My mom keeps a clean house, but she's not a perfectionist about it, so I don't think I can attribute my habit to her. I've even been known to pick up brooms in friends' houses, unbidden, and begin sweeping their floors. It's just what I do.
So, yeah, there's my idea of hell....being invited to your house and your floors are filthy gritty dirty and you have no broom.