The first puzzle that Steph and I attempted in the Hunt was "lol". Someone on our team had labeled this one as involving puns and memes, and all it took for us to jump into it was the p-word. The puzzle presented a series of pictures, each with a phrase in the style of a particular internet meme on the outside and a seemingly incongruous image in the inside.
What we did
List of sheep breeds, a Wikipedia page I never thought I'd see myself visiting.) Seeing no obvious patterns among the image names, we tried to identify the name of each meme "archetype". That proved more difficult. Besides not being too educated on internet memes, those that we could identify were often a little ambiguous. Without a clear sense of direction, we gave up on this one with all but one of the pictures identified and weak guesses at about half the meme archetypes. The rest of our team contributed a few more meme archetypes, but we were never seriously close to the answer.
What we should have done
Identifying both the image and the meme type was exactly the right idea. From there, we were supposed to notice that each image name and meme name had exactly the same number of letters with the same space pattern: potassium ion and chemistry cat, etc. Then, the image and meme had exactly one letter in common in the same position (S for the potassium ion and chemistry cat example). Taking this "letter in common" for all the pictures gave a clue to the final answer.
Would we ever have figured it out?
Possibly. Upon later reflection, a puzzle full of internet memes was not the best choice given my general frustration with internet subculture, but presumably some corner of the internet has a catalog of memes. The "aha" moment of noticing the letters/spaces pattern might have taken some staring-at, but it's not out of the question that we would have seen it eventually.
Matrix Morpheus, which makes sense now that I know of Matrix Morpheus as a meme, but our team decided it fit the Condescending Wonka meme before we even considered Mr. Morpheus, and I never thought to disagree. Similarly, "Completes Sunday NYT crossword with a pen" sure sounds like something one of those meme-y wolves might say, but who's to say it's the one with a gray background instead of any of the others?
The counterargument is that once a solver has seen the pattern, that knowledge would allow a "weeding-out" of the meme archetype possibilities to include only the ones that matched the letter/space pattern of the accompanying image. But that essentially requires solving one part of the puzzle by solving a different parallel part of the puzzle, which seems clumsy.
What can this puzzle teach about good design?
The solution to a puzzle, and to its intermediate steps, should be absolute and unambiguous. The most obvious answer that fits all the criteria of being a plausible answer should be the answer. In other words, a solution should depend only on what clues are contained in the puzzle and not on meta-factors like the nature of the puzzle itself.
Puzzles don't always follow the maxim of "the most obvious possible answer should be the answer." Crossword puzzles, for example, are notorious for incorporating same-letter synonyms or competing transliterations ("tsar" vs. "czar" is a favorite). But puzzlehunt puzzles would do well to eliminate judgment calls wherever possible and focus on the mechanics of the puzzles themselves.