The "Pretty Girls, Ugly Faces" photo fad has been around for a minute.

But it's one thing to take a photo of your pretty self and follow that up with an ugly face pic — and it's another thing entirely to do both frighteningly well, in reverse, in a single take — on video.

"Gak do eh jung yo sung," or "the importance of angles" says the Korean girl whose masterful contribution to the meme is making the rounds today.

And for obvious reasons: She's clearly teaching the world a very valuable lesson, which is that there are some parts of YouTube best left unexplored.

(Think you can do better? Tell it to the comments section below.)

[H/T: Reddit via Daily Picks and Flicks]