Face is a four letter word.
There really is nothing like watching my son's face. While he plays... while he eats... while he sleeps... while he is thinking or coloring or singing... or just sitting there. It isn't always a happy face... and I can't say I like it when he pouts or screams at me... but even those times it is amazing to see the total transformation of his face.
The best thing, of course, is when I see that face break out into a grin.