I've done this and actually find it a bit disturbing.
It's great when I can't solve a problem in the evening, get a good nights sleep, and then I am able to quickly solve the problem in the morning. Sometimes though I actually have dreams about sitting at my desk writing the code that I couldn't come up with during the day. On the one hand it's great to wake up in the morning with the solution to my coding problem. But on the other hand, I'm not sure it's healthy to have my dreams filled with the same thing that I do all day while awake. Whenever that happens I definitely make some extra time for my hobbies that don't involve computers.
Next morning I looked at the note and it was exactly right.