I photographed my son Ethan today out in the backyard, playing around with different background textures. He was terribly aggravated the whole time - "my legs hurt", "the sun's in my eyes", "there's bugs biting me", "i'm itchy". When I told him to smile, he gave me moldy cheese-ness so after a while, I'd say "ok - look over my shoulder. don't smile though. don't smile.
don't smile." Of course this immediately rendered giggles and "viola!" - beautiful photos of my serious son.