Whiplash is a movie stripped right down to the bare bones. No fat, no unnecessary filler. It's raw and real. The performances are engrossing; I never see the actor playing the character, only the character themselves. The story is tightly written to the point where you can point out the plot progression and you know when a new story beat is happening.
And do I even have to describe the music? Jazz is probably the best kind of music out there, and Whiplash feels like a sort of twisted love letter to those who won't let the good ol' days slip away.