I actually find it quite disturbing. When your conscious mind has been very focused on something the whole day it will naturally keep the momentum. That in turn makes it difficult to fall asleep and when you do the sleep is often quite thin. What I figured is that if you find a way to turn your mind off either with meditation or some distraction (for example movie or book), the sleep is much better and the next morning is usually much more productive and often the mind comes up with some suprising new ideas.