When my niece has finally settled down for the night and snuggles with me in my favorite chair while we watch TV before her bedtime... That is one of my reasons to be cheerful.
My youngest baby does that too. Don't you just love it when they lay their head on your shoulder and just fall asleep? Or when they fall asleep with your hands on your face as the go out for the night.
When there is unconditional innocent love, you have peace and happiness at the same time.