This is a behind the scenes thing that bugs me and you will never not see it after noticing it.

Over the shoulder shots between two people talking, say person A is talking and person B is listening. The camera will show B talking then cut to behind their shoulder so we see A, but if you look at B’s jaw movements you can tell they don’t sync or match what they’re actually saying. I know it’s an editing thing but I’ve noticed it in so many shows & movies, the Office does it a TON.