Earlier this month Daniel Day Lewis won a BAFTA for best actor for his portrayal of Abraham Lincoln (the 16th President of the United States). He is also favourite to get the Oscar for his performance as well.
What many people don't know is that Lincoln suffered heavily from insomnia. How can someone who had such a powerful impact as a leader perform so well for so long whilst suffering from insomnia. There have been suggestions that although he didn't manage to sleep for long each night when he did sleep it was of a deeper level. It's reaching that deeper level where the real benefit of sleep is most felt. This is where the idea of quality or depth of sleep comes in. More here: http://sleepora.com/sleepblog/how-the-depth-or-quality-of-your-sleep-is-more-important-than-the-quantity/