There's a moment near the end of the movie, when McManus and Keaton are searching the ship for the cocaine, killing everyone they come across. We're in a long shot through a doorway, looking at McManus as he moves forward through the room. There's a dog in the room (I think it was some kind of German Shepherd mix although it also had kind of a fuzzy terrier muzzle as well) and at this point you kind of expect McManus, played by Stephen Baldwin, to shoot the dog and keep going, or for it to attack. But McManus just moves through the room, pets the dog's head for a moment, and keeps going.
That, to me, is art. Someone, be it the screenwriter or the director or Baldwin himself thought through that scene, which is maybe ten seconds long, and made a decision. And it makes sense if you think about it. McManus would totally be a dog person. He doesn't get along with people at all, but he values loyalty, which the movie has already established through his relationship with Fenster. He may be a thug, and a thief, and a ruthless killer, but he's also a sniper, which lends itself to a certain economy of violence, and a man like that doesn't shoot the dog if he doesn't have to. (Hockney shoots the dog if he walks through that room, I think. Keaton ignores it.)