My son Lukas just turned six months old and is all giggles. Everything is funny -- getting poop on his foot, being spun up in the air as high as I can hold him, spitting up all over me -- and it's just an amazing feeling to be around him. He cries, as all babies do, but it's usually obvious when that will happen (waking up, bumping against something, dirty diaper). Back when he was just a few weeks and then a few months old, he would do this thing where very, very subtly his smile would morph into a frown, like a slow-moving flipbook. His expression would end in what we called "the mad face." And before I could say, "Uh-oh, it/s the mad face...." he would start to wail. Sometimes I miss the mad face.