Just compare her Olympics guffaws to her expressions at other events.
Here's Kate Middleton watch sprint track cycling at the Olympics.
Image by CARL DE SOUZA / Getty Images
And here she is while Prince William makes a speech at a reception.
Guys cycling really fast around a track? Hilarious. Your husband making a speech? Boring.
Image by JOHN STILLWELL / Getty Images
Here she is at the Equestrian Jumping event at the Olympics.
Image by LUKE MACGREGOR / Reuters
And here, leaving a Cathedral service in honor of the Queen's Diamond Jubilee.
Image by ANDREW WINNING / Reuters