Precious Smiles

One of Colin's new habits: smiling and laughing while eating. He'll look up at me out of the corner of his eye, and for no reason that I can fathom, will smile. I reflexively return the goofy grin, and then he starts to laugh. He'll take another swig or two, then smile and laugh again.

What on Earth is the boy thinking? What is so funny? And what happened to me that I'm now so endlessly amused and entertained by something so simple?