Easier to go unnoticed
Last night I went to bed a bit late, due to my Krav Maga class: got home, showered, put on some laundry, and etc.
So today, I was a bit tired. My desk faces the main route that people walk along on our floor -- meaning that most people can't see under it. So I crawled under my desk and took a nap during my lunch hour.
Since I was "clocked out" for lunch, it was a perfectly legitimate thing to do. But to avoid questions, prior to my nap I shifted some things around to further shield myself from view.
Once of my co-workers said there was some precedent: George from Seinfeld.