CDO

I came across this a while back on StumbleUpon and included it on page 10 of my notebook.  It cracks me up every single time I read it.
"I have CDO. It's like OCD, but the letters are in order as they should be."
So I guess that would make it Compulsive Disorder Obsessive, which kind of makes sense when you think about it...OK, not really.