Ahh, there's the mystery! Actually, I just couldn't come up with a clever answer to the question...
What brings this to mind are two books I recently read that I very much enjoyed. Both employ many of the literary devices we expect in mysteries, but each to different ends.
The first, "Started Early, Took My Dog" is the fourth of Kate Atkinson's novels featuring 'retired' detective Jackson Brodie. Her first in the series is "Case Histories", and upon its release, Stephen King raved that it not only was the best mystery of the year, it was the best of the decade. What I like so much about this series is that, yes, there are mysteries to be solved, but Atkinson also explores the mysteries of the human heart -- why do we do what we do? So much of the plot is delivered in interior monologues that the characters become fully fleshed out. You can start with any of the 4 books, but you'll get the full effect if you start at the beginning.
"Heads, You Lose" is a meta-comedy disguised as a mystery. Lisa Lutz and David Hayward previously dated, and Lisa (the more famous of the two) decides they can put the past behind them and collaborate on a mystery novel, each one writing alternate chapters. That part is true, mostly. What makes the book fun (and flat-out hilarious) is that upon this frame is hung an experiment in developing the story, AND commenting on how the writing goes back and forth. Lisa and David become fictionalized versions of themselves in the book as they each make snarky asides about the other's plot twists and quirky characters. David introduces a character Lisa hates, so she kills him off when it's her turn for the next chapter. And suprsisingly, the actual story itself makes for good reading too.
So there you go -- two very different takes on the mystery tale that still manage to scratch you where you itch (mysteriously speaking). Enjoy!