Let's be realistic.

I'll tell you why so serious

A lot of perfectly good film show their cards early, establish a unique premise and let the audience explore a topic at a leisurely pace, without much in terms of surprise. this film is not one of those films.

This is ultimately a movie about the very bad things that can happen when we don't address our unease, when we just try to brush it off, whether that's to fit in or to preserve our self-image.