Why do teenage girls pull stupid faces in photos?

[Emma]

It is NOT cute....it makes you look even uglier.

 

[Veronica H]

Im sick of it, lets cut their faces!

 

[Mr. Herbert 愛]

They think they are cool, however, they are just being total idiots.

 

[Holy Smokes I'm Gorgeous]

Ughh.. I know what you mean.
Like the puck (is that what it's called) with the lips... or when they blow air into their cheeks.

 

[Daphne]

To appear as if they have a funny personality.

 

[Mr. Goodkat]

I always think they look like Ben Stiller in "Zoolander" trying to pull off the Blue Steel pose.