Drinking from an empty cup is always weird, and very noticeable, especially when it's a disposable cup. You can tell the way they lift it that there is no weight to it. Why not just put a bit of water in it?
Action movie fight scenes with one good guy and several bad guys. The bad guys take it in turns to try and take down the good guy, one at a time. Every Batman film has him heavily outnumbered by goons at some point in the film, but the baddies all join a queue, and patiently wait for their turn to take a swing at Bats. Just pile on him.
If the scene in a film/show goes down to the subway, someone is getting done in. There's never a subway scene where someone just carries out their commute. Only bad stuff happens in the subway.
When someone is on the phone, and they get hung up on, the dial tone is audible to the viewer, but the person on the phone will keep saying "hello?! hello?!" like they don't know what a dial tone is, and that the dial tone is going to be interrupted by the call reconnecting.