Sometimes there’s a scene that is particularly challenging. It may be because there’s something not working, or perhaps there’s a higher than usual level of complexity. Or it may be that you simply don’t know how to solve the specific plot problem that requires solving.
This last scenario is when it’s good to talk it out with someone. I don’t necessarily mean someone who can participate in the discussion. A monologue can be just as effective. Somehow the simple process of describing the scene and explaining the problem can unclog the brain and ideas fall out. Even if your companion can’t get a word in and stares back at you bewildered.
Of course, often the different perspective offered by a good sounding board can help too.