I’ve long found the statement “that’s a good question” to be obnoxious. As I tend to think questions through, trying to answer them on my own, I find the statement redundant. However, I’m rethinking that annoyance. There are bad questions. Asking questions that whose answer is evident are a particular bane of mine.
A good question has some basic pieces: thoughtfulness, insightfulness, and (if its particularly good) the answerer learns something. Good questions show that you’ve paid attention and have considered things.
A bad question is one based in intellectual laziness. Asking questions to avoid thinking, researching, etc, is obnoxious. So, think before you ask.