You get to reflect on things and you just get to sit and listen to your own thoughts.
It is amazing how much that can do to you. You hear your soul and you can feel your own feelings. It surprises you how much there actually is to think about when you actually get down to it. But even the stressful thoughts at these times are calm because it is so relaxing. Everything is just taking it's own time. So whatever your body has to feel, it is feelings it. Whatever you need your head to listen to, it listens.
I can't explain the feelings, so try it yourself. No music, no tv, nothing. Just you. and maybe even a book. But then lay down on your back and just look up into the ceiling and let your heart and mind wonder.
This is sounding all meditating or whatever, but not really. Not even soul-searching. I like to call it "You-time"
Have some "you-time" :)