I generally sleep like a baby...fetal position, mouth open, smiling, peaceful...and I generally wake up well rested.
The exception to this is when I have a problem in my mind that I need to solve. Similar to my dad, when I go to bed mulling over an issue, I tend to wake up at about 3 am with a solution running through my head. Of course I then need to get out of bed to write it down so the answer is not lost.
Obviously this is not a good habit to cultivate on a daily basis so thankfully it happens rarely, but the expression "I need to sleep on it" has tremendous value for me. Many times by morning I have resolved what I need to do.