The final performance showcase is a masterful display of editing and sound.
Andrew gradually growing more confident in his abilities, to the point where he stands up to Fletcher.
Andrew's father going full Papa Wolf and getting Fletcher kicked out of teaching after the latter endangers his son's well being.
The point where Andrew is able to fill in for one of his classmates in a musical performance after losing the sheet music, as he had practiced so much that he memorized the music himself.
Andrew calling Fletcher’s bluff when he says “I can cut you any fucking time I want.” Andrew responds “You would’ve cut me by now.” If it weren’t for the horrific car crash afterwards this would have probably been the start of Andrew finally besting Fletcher at his own psychological war game.
Admit it, you were cheering Andrew on when he attacked Fletcher onstage, and for once actually made him look terrified.
As sad as it is in context, Nicole telling Andrew off for getting so self-centered in the pursuit of greatness.
Andrew's final drum solo at the climax of the film is a great moment of catharsis for both him and the audience, as he finally lets his talent shine and sticks it to Fletcher at the same time. And Fletcher can do nothing but watch.
Andrew(mouthed): Fuck you! (A couple minutes later.) Fletcher(leaning over the drum kit): I will gouge out your motherfucking eyes— (Andrew hits his crash cymbal, thwacking Fletcher in the chin with it and forcing him to back off.)
Even better: Andrew gives such a display of brilliance and passion while playing that, when his cymbal falls after he hits it too hard, Fletcher jumps to fix it, so his performance goes unhindered. After that, we see Fletcher giving him visual cues and mouthing his silent encouragements, and eventually awarding him a (subtly framed-off) smile and nod of approval right before the finale.
The making of the film for Damien Chazelle. On only his second directing job, he managed to make a completely professional looking work in just 19 days, the last few coming after he was in a car accident to rival Andrew's in the film.
J. K. Simmons's entire performance. He plays the role of a cruel, monstrous and sociopathic man to absolute perfection (all the while, he was reportedly the complete opposite when the cameras stopped rolling) and is generally believed to be a major reason the film did as well as it did. He gave an iconic career-defining performance, went from being a respected character actor to a household name, and won a well-deserved Oscar in the process. Even Fletcher would probably have to admit he did pretty well. Particular emphasis must be given to the "Rushing or Dragging" scene. Simmons and Teller's performances combine to create one of the most intense scenes in of cinema in the 2010s.
