How many DMs claim they feel when their players bypass an encounter that took a lot of time to plan with a crazy, inventive solution that was both brilliant and foolish, but somehow worked:

How DMs should actually feel:

I want to put an end to the idea of angry DMs whose plans were thwarted. Your players did something cool and unexpected. That's awesome, not a reason to be upset, because in D&D it isn't players vs DM, it's players vs the world, which the DM creates to make the story compelling and challenging. And guess what? You can use that encounter later (after a few changes to the environment and theme, and that make the old solution implausible) and they'll never know.

I'm taking a short break from social issues to offer the following advice for D&D (and other rpgs) game masters:

When placing riddles/puzzles in your game that are important to the story, always include an "out" condition that doesn't require the players to solve it.

For example, you might have a classic riddle that opens a door, but giving the wrong answer causes an automaton to come to life and attack the party, and destroying the guardian lifts the seal, or reveals that it's power source is the key to the door, or something along those lines.

Similarly, you might have a container or door that is unopenable unless the players solve some kind of puzzle, however the object/portal can also be opened by sufficient brute force, a.k.a "I smash it." Doing so however triggers some massively damaging effect to the party, be it mechanical or magical. This gives the party the reward, but at a cost they would not have incurred had they solved the puzzle.

This doesn't need to apply to incidental encounters, such as a door to a treasure room; it's fine to put luxury items/rewards out of reach of players who can't solve your tricks.

On the topic of finding puzzles and riddles, that's as simple as a Google search.

Google a term like "shape puzzle" or "wordplay riddle," dig eight or nine pages into the results, find an article/post containing some good riddles, and try to pick them randomly from the middle of the list. This reduces the chances of your players already knowing them from games they might have made, since too many people literally take the first five riddles/puzzles form the first page they find. If you're in an online game where your players can Google the riddles without your knowledge, you should also reword them enough that it'll be hard to find with a quick search.

Happy gaming, all.