Does that mean we don't really know what we're writing or talking about? I sometimes think so. But to put a more kindly face on it, I'd say us writers don't expect our readers to understand what's going on until we explain it to them.
The explaining takes a lot of different twists and turns and involves many different people.
So what makes a good mystery? Plot is important, of course. Without it, there would be no mystery. But I think the most memorable mysteries are those featuring truly memorable characters.

Most familiar in the classic hardboiled ranks are guys like Dashiell Hammett’s Sam Spade, John D. MacDonald’s Travis McGee, Ross Macdonald’s Lew Archer, and Raymond Chandler’s Phillip Marlowe. From a different perspective, there are Agatha Christie’s Miss Marple and Hercule Poirot, along with Dorothy L. Sayers’ Lord Peter Wimsey and Harriet Vane.
Coming down to the present, the list could go on and on. Fortunately, there are lots of contemporary authors creating memorable characters.
But the question remains, is plot more important in creating a memorable mystery, or is it character? What do you think?
Chester Campbell
Murder Mania