We've all seen great actors and actresses who are missing a certain chemistry. And it's not about getting along or not getting along.
See my father knew a lot about music, he played the piano and he would do theory and stuff like that, but I didn't learn anything from him, but I played that for him and he liked it a lot.
If a movie is really working, you forget for two hours your Social Security number and where your car is parked. You are having a vicarious experience. You are identifying, in one way or another, with the people on the screen.