The Sicilians scene from True Romance.
(In fact, many scenes from True Romance, the scene with Drexel, the final shoot out, the 'You're so cool' scene...)

The opening of Natural Born Killers when they kill the people at the diner.

Very sad to watch now that both Hopper and Scott are dead.
https://www.youtube.com/watch?v=oepJFDXuHmI