I recently did the following:
latex test.tex
$ bibtex test.tex
I couldn't open file name `test.tex.aux'
Once I had tracked down the cause of the problem, I felt stupid for not having noticed it earlier -- but at the same time, I wasted five minutes on it. I then posted a Q+A; my reasoning was that I wanted to save time for anyone else who hits the same problem.
(Also, even if it's only in a small way, I want to give something back to the site. I ask a lot more questions than I answer. That's usually because all the easy questions are snapped up before I reach them, so recording simple things like this is one of the few ways I can provide answers.)
In any case, after I had posted this, an experienced user noted that this common problem was warned against in every LaTeX manual. After a short discussion, I wrote:
if it is the case that some questions should not be asked because everyone should know better/it's in every guide, it would be great to have that policy documented somewhere
I'm following that user's suggestion and opening up the question here: is it alright to ask and answer questions about issues discussed in every LaTeX guide? I might add that one reason I'm inclined to do so is that the last time I had time to read a LaTeX guide cover to cover was about 10 years ago; now I try and pick things up as I need them, and when I hit errors Google and this site are my first two ports of call.
Edit: also, my reasoning was that this kind of sentiment applied: because this is a website rather than a paper manual, and it has a search function, adding extra material doesn't impose very high costs on anyone. But perhaps you will disagree with me about that...
This may also be relevant: How "elitist" should the site be?