I would have to say this is probably one of my biggest vices.
I live off of to-do lists and schedules. I make plans and do my best to stick with them. I do everything in my power to run things "smoothly" whether events or relationships.
But on the plus side, it does allow me to accomplish a lot during the day since I am so scheduled (I even schedule in free time). And it helps me in my career as well (one that needs a LOT of organization!)