I've given the "(I know the answer but) this is a dumb question" in response to "using two stacks, how would you implement a queue".

I think being able to implement a queue using two stacks is kinda neat. But, nevertheless, it's not a good interview question.

IIRC they wanted to know the efficiency of different algorithms like big O notation stuff. Maybe it would be understandable if we were doing high performance real time programming in C. The job was writing HTTP APIs. I aced all the HTTP and SQL questions.