Most of us in the English speaking world are most comfortable when reading left to right. Because we’ve been trained to consume information with this direction in mind, it has implications on how we watch films and interpret other forms of visual media. Generally speaking, it feels more comfortable when we watch sequences of shots that follow this same “left to right” rule.
For example, if a person enters a scene on the left side and walks towards the right, the next shot should include a shot of them continuing with this left to right motion and they should enter through the left frame and walk towards the right on subsequent scenes (as long as the direction and movement within the scene calls for it).
As a filmmaker, it’s up to you how you present your story visually, but it’s important to know that reversed direction (that is right to left movement) creates a sense of tension.
That being said, reversing the direction of movement can work to your advantage if you’re trying to show either changed direction or you’re trying to exaggerate the passing of time.
It’s important to know these rules before you start filming so your shots are well thought out and intentional. A lot is to be said for leaving room for spontaneity and breaking the rules, but a technical error is a technical error. Even if audience’s can’t articulate their expectations, they have predetermined expectations due to the precedents set by earlier films, as well as by using their own common sense.
If you plan on challenging film convention, just make sure you do so in a strategic way. There is a big difference between strategically breaking the rules of filmmaking and sloppy filmmaking. Just make sure you’re on the right side of the fence and know the rules first.