What are your thoughts on creating a canonical question & answer for all queries related to Trailhead Module challenges or Superbadge challenges?
Questions related to superbadge challenges are usually frowned upon and shouldn't be encouraged in this community (as it would defeat the purpose of the solving the superbadge or a module challenge). However, there are quite a few annoying things that can block someone from getting thru the challenge and these are sometimes unrelated to the actual problem itself. I was attempting a module challenge today (a really simple challenge on this module) and while I had the correct solution from the beginning, I had forgotten that I had created a validation rule on Account object earlier which was blocking the test code from running successfully. After 30 min of breaking my head around modifying the simple apex code, I realized my blunder. Deleting the validation rule and running the apex unit test solved my problem, but running the apex unit test was not really a part of the challenge. For newbies who are stuck in such scenarios, it can be a quite discouraging and I wouldn't blame them if they post questions on SFSE seeking help.
I guess providing suggestions on things to watch out for while solving a trailhead challenge (such as running apex unit tests, deactivating validation rules that aren't required etc.) should be helpful.