Time to run this one into the ground as well. It's basically AIDS, but for real life.
The OCD is the most easily identified, or among them. They're the ones who got trapped inside your school's trophy display case after adjusting each award so that they were arranged from shortest to tallest. They're also the ones who have to have their pencils all at the exact same length, and has their bookshelf at home alphabetized by the second letter of the seventh word in the book.
The OCD is like a superhero. Except obsessed with putting things in order instead of being able to fly. During times of peace, they're that guy who works three cubicles over from you and gets a double latte in the morning. But when something is put out of order, BAM!, they're rearranging it needlessly in no time at all!
Now, the OCD brings both benefits and drawbacks to the table (Neatly arranged in two separate stacks, of course). I'll start with the benefits. If you need any sorting (Laundry, legal documents, computer files) just mention it offhandedly near them, and they'll be on it without your needing to ask. Menial tasks such as refilling the printer paper, and picking up a bunch of dropped supplies will be done with happiness by the OCD, and if you want to mess with them, make a habit of dropping uncooked rice and sesame seeds onto the floor.
But this can turn on you. When you're trying to enjoy your sandwich at lunch, for instance, it can be a little bit annoying having someone making sure that the top piece of bread is being eaten at the same ratio as the bottom piece. Later, when you're trying to write a report on your company's earnings, you might get annoyed when they sort the words in your document alphabetically. And once they start complaining about how the cars in the parking lot need to be arranged chromatically to make a rainbow, that's pushing it more than a little.
Once you get to that point, you'll have to reel the OCD in. There are multiple ways of going about this, but by far the easiest is to become the anti-OCD. This means you will have to intentionally cause chaos within the "natural order of things". It's not that hard. Hang your jacket inside-out on the door. Turn the paper towel rolls in the bathrooms backwards. Come to company meetings with one thumb completely blue.
If the OCD isn't tearing their hair out (Okay, I lied, the only thing to make them less OCD is pills) by now from your techniques, they might be a FCDO. In other words, a Fake OCD (Trying to prove they're OCD by alphabetizing the letters). These people will tout their "OCD" like a banner, shouting louder than that one loud guy that they are OCD, then turn around and not try to make all the windows on the fourth floor open exactly 45 degrees. Introduce these people to an actual OCD (By locking them in a room with the OCD for a day) if they become too annoying. They will no longer be "OCD" the next day.
And just in case you're OCD...