Sometimes you'll be shooting something, then get a feeling to impulsively pan away because the shot isn't great, or it looks like something more interesting is about to happen elsewhere...
...then you pan the camera away, and the new shot's not that great either.
Either you sneeze, or the person who was going to walk into your composition realized they left their keys somewhere, or a cloud goes over the sun, or traffic stops in front of your camera - whatever.
The most common idea at this point is to either abandon the new shot completely (turning off the camera, for example) or quickly panning back to your original subject.
See what's going on here?
It's kind of subtle, and also a common rookie move.
I know with myself, when I first started making documentaries: I'd be shooting something in the wild, say, two people talking, and nothing really "happens" so I swish pan to something else - say, a bird in a tree. I pan to the bird, but the bird flew away before my lens landed on it. And then back over my shoulder I hear the two people I was recording just moments ago, laughing. I swish pan my camera back, and they're hugging and saying goodbye.
The entire time I'm thinking: "If only I committed to a composition."
When you commit to a composition for a minimum amount of time, you increase the possibility of capturing a cinematic moment.
With documentaries, you're continuously capturing footage, but you're also trying to capture the most amount of useable continuous footage possible.
So here's two tricks related to this idea:
1) The next time you're filming documentary footage, when you get the urge to change compositions, ignore it.
Try staying with your current composition for twice as long. See what happens.
(You'll probably capture something totally unexpected & wonderful).
2) The next time you switch compositions but there's nothing exciting waiting for your camera at the end of the switch, stick with the new composition anyway.
Wait at least a minute before changing the shot again. Count to 60 in your head.
Even though nothing may be happening in that exact moment in time, the likelihood of someone / something magically appearing in front of your lens is quite high.