Those faces may be youthfully lovely. But there's nothing beautiful about being angry or being the target of another's rage.
Looking at the photos from left to right, 1,2, 3 & 7 are most likely laughing or being raucously funny. Five may be fed up and shouting "I don't want to hear anymore of this. Six is finding something disgusting and outrageous.
I believe only the image in the centre shows real anger. Note how the insides of the eyebrows pull down, how the lower eyelids squeeze up but with no creases at the corners of the eyes. Observe the tension in the way the tendons of the neck stand out. Notice the direct, front facing, locked-on gaze. When someone is really in a rage, they rarely take their eyes off the target of their anger. It's instinctual. A human is the most dangerous animal on the planet.
I don't know. I am experiencing an emotion and looking through my own eyes. I can't see my expressions. I'm not thinking at all about what I look like. I am sure it is not as pretty as other moments I live.