Modern American society has lost the art of the riddle.
We have riddles, to be sure. They're all jokes, which isn't a problem with the form in the least - humor takes a great deal of talent to devise and deliver, and any form that can't be used comically is an underdeveloped one. The trouble is that they are for children, and children are lousy at comedy. Awful, really.
One of the best jokes I've ever heard a child invent comes from a girl I used to babysit. She's a bright young woman now with a totally normal, even sharp, adult sense of humor, but when she was about seven years old she had a favorite joke. "What's green and very dangerous?" she would ask. When you admitted a lack of knowledge, she would very proudly and confidently proclaim, "A pickle!" Then she would start giggling and run away and hide. (She was also very good at hiding. Even if you followed her after she told the joke, you wouldn't see her again for at least ten minutes.)
There are two problems here. One is that we encourage children to explore riddles before they're ready to be any good at it, which wouldn't be terrible as an introduction if we didn't then encourage them to stop right when they're finally getting good.
"Why is the chicken's stomach shaped like an egg? Because it lays too many."
When children are very young and first introduced to riddles, the natural developmental process is such that the feature they most notice is that the answer is known to the person asking, doesn't have to be literally true, and usually is something surprising. The concept of a punchline isn't even necessary (children that young often find all manner of surprises humorous), leading to jokes like this one: "What does a cow called with no legs? A clown." The fact that the joke makes no sense whatsoever is not a problem for the child who invented this joke.
A little older, and jokes start to be something to collect. There's status to be gained from knowing more riddles, and that status can be maintained in part by insisting on the exact right wording of the answer; mostly, however, it accrues to people who have more riddles that others might want to tell. Again, adult notions of what makes humor work are irrelevant; what matters is that there is a right answer, and other answers are wrong, and the right answer can be learned. With a little development, "dirty jokes" are especially prized, even if they aren't any good. (One of the favorites from my own middle school days: "What's a 6.9? A 69 ruined by a period.") Jokes invented under the influence of the first glimmerings of the dirty joke phase often have no point to them except to mention bodily functions: "What do you call people? Doo-doo people!" These are not riddles invented by somebody intending to write non-comedic questions of the sort found in early Germanic cultures, but they also aren't the work of anybody who actually understands what makes anything funny. When comedy does emerge from this process, it is by chance.
"Why did the chicken cross the road and go back again? Because its bum fell out."
Of course, the impulse to create is often quite strong among children. That means that riddles of this quality are invented with great frequency. One of the producers of This American Life once went to a public elementary school playground to record children telling Christmas jokes. He found that there aren't actually any Christmas jokes, but that every third grader he approached was willing to invent one on the spot. "What did the Christmas tree say to the menorah?" one asked. (This after explaining to the interviewer, Jonathan Menjivar, that her family celebrated Hanukkah rather than Christmas.) "You don't have decorations like me, I'm more popular than you." (When Menjivar didn't know how to react and came up with "Wow, the Christmas tree is mean," the girl simply said, "Yes, the Christmas tree is mean. But the menorah actually has very good intelligence.") One of the Christmas riddles even actually worked as a joke, on its own terms: "Why didn't Santa deliver any presents? Because it wasn't Christmas."
Eventually, of course, children get old enough that they start to have a sense of humor that actually requires both that the joke and its punchline have some kind of logic to them, and that that logic work in an unexpected way. (That's not enough for something to be funny, but for riddles of this sort it's definitely necessary.) That's when they start being able to actually appreciate humor in riddle form, to invent jokes adults might actually care about, and to curate a repertoire worth hearing. And right at that age, we expect them to graduate from riddles, which we mostly see as childish, and to tell jokes in narrative form instead.
"Where do cows go on holiday? France."
Narrative jokes are a lot harder to construct. In general, we don't try - although obviously they come from somewhere, and not just from professional comics, so some people do at least some of the time. (They also evolve - when one is written, the talent that goes into telling a joke well means that it will be passed along in the best possible way more often than not, and people will misremember some details, and over time the joke will get better as it travels.) Some jokes in this format are also invented by children before they're old enough to do so with any kind of competence: "A guy was at a shop and he bought some lobsters and said to the man, 'AAAAAGH it's a crab.' And the other man said, 'That's not a crab, it's an orange pencil.'" But ultimately, we expect that as they grow into being capable of actual comedy, children will move to retelling jokes of this form, rather than favoring riddles.
The result is that most people's competence at riddles - both at guessing answers and at composing them - peaks right when they're about to stop trying. And so if I ask you a favorite non-joke riddle of mine (which I learned from elsewhere, because I too cannot write a good grown-up riddle), I expect you to be utterly unprepared to answer it, although the answer suits the prompt nicely: "Gold in a leather bag, hanging from a tree / Money after honey in its time / Ills of a scurvy crew cured by the sea / Reason in its season, but no rhyme." Similarly, the riddle-game sequence in The Hobbit feels strange to us, belonging to what is now a foreign culture, despite such contests being a common Anglo-Saxon pastime.
"What comes up but never comes down? A pineapple."
The title for this post comes from a Louis CK interview, by the way, and one that illustrates the one upside of bad kids' jokes "You know, you know jokes after a while. Someone starts a joke, you know what's going to happen, but not hers. Here's a joke she [his 4-year-old daughter] told me the other day. She said, 'Who told the gorilla that he couldn't go to the ballet?' Right away I love this. This is a great joke. I don't know this joke! I said, 'Who?' And she said, 'Just the people who are in charge of that decision.'"
Of course, most of the jokes kids invent aren't anywhere near that charming. But when they are, we can't help but smile.
(Most of the jokes in this post are courtesy of badkidsjokes.tumblr.com.)