In an emotional interview with CBS news anchor Katie Couric, Laura Bush revealed that she is undergoing treatment for a rare medical disorder called fachus sardonicus (commonly known as Eternal Smile), which is distantly related to risus sardonicus (a symptom of tetanus that freezes face muscles into an evil-looking grin).

The First Lady's frozen smile is the result of decades of forced happy faces during public events. Over time, the facial muscles lose their inherent memory to return to a normal position, and remain locked in a never ending grin. The trauma of this condition was evident during the interview.
"It's obvious what the problem is," said Mrs. Bush to Couric. "Right now, I'm crying inside, but I look like I'm greeting a troop of girl scouts. Because of the smile, George thinks I approve of everything he says and that I actually enjoy his company. How do you tell someone you hate their guts with a huge smile on your face?"
Mrs. Bush sobbed several times during the interview. "I can't go to funerals, of course," said the First Lady. "And I can't be in the same room with Cheney who considers smiling 'offensive.' If it was more of a sneer, I'd be okay."
Couric asked if there is a cure for the malady, and Mrs. Bush shook her head. "Sadly, not yet. There are treatments that help lessen the severity, but a cure may be years away."

In an awkward moment, Couric looked puzzled and asked, "Did I say something funny?" to which Mrs. Bush responded with several colorful expletives.