In your plot, events (hopefully) will happen that move the story forward. Often, they only happen to put a necessary condition into the plot.
When you prioritize your own convenience in putting those conditions in place, you miss big chunks of the emotional story.
frinstance – you need the protagonist’s dad out of the way so the young protagonist has to protect the homestead on some Purge-like night. So, what to do with the dad? Anything will do, right? Business trip. But you can still get him on the phone, right? He’s not physically there, but he’s still available.
So you just put him in a coma in the hospital and call it done. But is it? This is a bad choice because everyone in the family, even though the plot is about something else, is going to be overwhelmingly concerned about dad.
And if you don’t make a commensurately large amount of storywork out of that, it’s going to look weird that no one in the family is thinking about dad, suspended in a life or death struggle, off in the hospital.
So this is the tunnel vision problem to be aware of. While you’re focused on how important it is for the kid to save the family, it’s easy to not notice what you let drop to get there.
You need dad incommunicado and away, and it seems not particularly important how you do it. It is actually a very big part of the emotional story, and depending on your ending and your thematic choices, he could be anywhere from deployed to in prison to living off the grid in New Mexico and the impact on your story is going to be very different, even if we never see his face.
TL;DR When you need a piece of plot to accomplish one thing, make sure you consider ALL the ways that piece of plot figures into the lives of your characters and relates to your theme.
