In Which I Review La La Land

It's not a romantic comedy.  My roommate didn't want to come, because she doesn't like romantic comedies.  That said, it's not a drama, and not a tragedy, and not a horror film and not educational and not action and not sci-fi, and while you might call it fantasy, it's not that kind of fantasy.
In a romantic comedy, there is a meet cute, and then an initial happy period, and then conflict (usually caused by misunderstanding), and then the characters sort everything out and live happily ever after.  And ... most of this happens.  But.
There's very much a moral to the show.  It is about following one's dreams and the compromises that that requires.  And it's okay to love someone and still not choose to be with them.  At the end there is a montage of "what could have been," but as it played, I kept thinking that it couldn't have been.  Parts of it, yes, if they'd made different choices, but it was the choices that they did make that led them on their paths to success.  It was their love that make some of their success possible, and their conflict also made some of their success possible.
The movie is very formulaic, but it's not stilted.  You know what's going to happen.  The show knows that you know what's going to happen.  Instead of trying to surprise you, the movie chooses to do the predictable things beautifully.  The music is beautiful.  The over-the-top dancing-in-the-clouds scenes are beautiful. 
It's not a romantic comedy.  It's a musical play in five acts.  Go see it.