Good stupid questions
I tried putting it into words, but it didn't turn out well enough. Will come back to this sometime in the future.
Stupid questions are the fun hard questions
I used to be in a small bubble of people, where we chased stupid questions. We had a lot of respect for them, and used to get extremely pumped when we found them. It became a habit for me - Coming up with stupid questions, and then trying to find their answers.
The group dissolved, but the habit remains. Now when someone comes up with a good stupid question, I have to control the impulse and not say out loud "that's a stupid question!", while getting excited about it (for obvious reasons).
(This caused an awkward moment in a closed room meeting once. I realized it much much later)
By stupid questions, I don't really mean questions coming from of a lack of specific knowledge. They aren't factual questions. Eg of bad stupid question: How does api x work?
Stupid questions are much deeper. They are pretty naughty questions that come up from a mix of knowledge and/or experience and/or luck. Novices rarely ask good stupid questions.
And answering these stupid questions takes a surprising depth of study and clarity. Most of what I know came from answering stupid questions.
Some examples I can think of: down stupid questions.
Naughty stupid questions also lead to amazingly robust engineering, as they are great for adversarial programming:
If you find someone who asks stupid questions on a regular basis, you've hit a gold mine.