I have never been an enthusiastic bed-goer, because I like life. But a nice thing about going to bed is that you can be confident that you are doing roughly the best thing. At noon, the smallness of the chance that your chosen task is really among the best ways to spend your precious moments in this world might be discouraging or oppressive. Perhaps you would only have to be a tiny bit smarter or think a bit longer to be able to recognize that this is the wrong way and that you could be doing much better. But at 4am, sleeping is probably pretty close to the most valuable thing.