For a few years I was sleeping about 4 hours a day on weekdays. I thought I was fine until I started sleeping 8 hours a day and realized I had been almost in a permanent bad mood for years due to bad sleep. My life completely changed.

Now even though I can still get through the exceptional sleepless night/day, the difference is so evident that my daily life is planned/scheduled to make sure I get plenty of sleep. Life feels a lot happier and fulfilling now.