During the last few weeks, I've read a lot. All genres. All time periods. I confess they've all been my "keepers", but that was deliberate because I was reading with a special purpose. I read specifically to analyze why they worked.
I concluded it's not enough for a book to be exciting, or have a wonderful plot, or memorable characters or description or action. It must hang together. Um, what do I mean?
Well, for ever cause there must be an effect. A simple (often used) example might be the letter that doesn't reach the recipient, therefore leading to some action on their part (such as leaving town) so the h/h never get together. There are many variations of this theme especially in romances.
There are others, though, not as obvious, but just as important. The heroine turns right at the intersection instead of left, thus allowing her to see the hero with another woman (or visa versa). Or the protagonist has a flat tire which places him in a vulnerable position while fleeing from the antagonist.
As I read, I noted the great skillfulness some authors had when dealing with cause and effect. And some beat the reader over the head with the result, taking care to "explain" while others assume the reader will be sharp enough to understand the way the threads come together weaving the picture.
There were some authors who left dangling threads. In some cases I believe the danglers were deliberate, allowing for another book or two. Others...I'm not so sure. They just might've dropped that stitch. Sometimes minor stitches don't affect the overall story, though I personally find them a bit niggling. Not immediately, but later in the middle of the night when I'm going over the story in my head.
Cause and effect. How do you use them in your stories? What's your favorite example from someone else's story?