Do you or someone you know have a pet facial expression?

Okay, I admit it—this is an odd question.

Seeing this photo of Mr. Clinton made me think how often I’ve seen him clinch up his mouth when (I presume) he was trying to look pensive—and that made me wonder what facial expressions I must repeatedly make to communicate how I’m feeling or at least wish to appear feeling.

Do you know someone who has a facial expression or bit of body language you’ve seen again and again and can describe it, or… if you were someone else looking at your face, what expression might they have often seen on it?