Back in my days as an English teacher, I remember telling my students (after I first learned this from somewhere else) that the popularity of the mystery is driven by our need for order. Unlike the messiness of life, in a mystery there is always a tidy end. This is very satisfying. Also, the evildoer is usually caught, or at least identified. There is none of that frustration we feel in real life when that undeserving snake we have the misfortune to know sails off smugly, the apparent darling of fate.
In high school when I moved my bedroom down to the basement, I shared the space with shelf after shelf of my father's discarded who-dun-its. Since like any card-carrying teenager I would rather have sat next to the nose-picker in geometry than spend any time with my parents, I spent many hours down there working my way through the entire Nero Wolfe series, most of the Miss Marples, and endless Margery Allinghams. I still read mysteries today and never do I concern myself with the actual clues. When I get to the finish, I think "Oh, so that's how he did it" rather than "Aha! I was right - the fingerprints on the elevator buttons were only a ruse!"
I read mysteries for the characters within them, which is why I regret that Christie didn't write more Tommy and Tuppance (spunky and fun) and less Hercule Poirot, (annoying). (Haven't you ever wanted to grab the man and say, "Buy some shoes that fit, you fool"?) I'm just along for the ride, enjoying Lord Peter Wimsey's urbane world and Miss Marple's cozy St. Mary Mead.
Now while struggling to write my own mystery, I realize to my chagrin that I suppose I'll have to put some clues in it. Hard work. I regret my past cavalier attitude and wish I had paid more attention to the masters when I was reading from one end to the other of those paperback-lined shelves.