This happens to all of us girls at least a few times. [And if it has never happened to you, either you haven't lived, you're lying, or you're probably a way better person than me.]
Homegirl is weeeerrrrrkin' it.. then decides to turn around and see the lucky fella, only to realize he is less than pleasant. This face happens.
[screen from YouTube]
I know it's hard to see, but it's there and it's real. And we're not really sorry, dudes.