When he told me the main value of recursion was avoiding state I disagreed with him [e.g. a chess engine is highly-recursive potentially but shares state]. He kept going with all-or-nothing questions and then responding to my answers with "eh..."
Eventually I said, "Hey can we put this on pause for a second? I'm not sure how you think this interview is going, but for me it's not feeling like it's going so well... I feel like the questions I'm getting asked are really put-you-on-the-spot type questions and then you're disagreeing with my answers but not explicitly so I don't even get a chance to explain my position.
After a while he said "Listen I need you to prove to me why you're better than 9 other candidates," at which point I knew I couldn't work with this person at a personality level. To that I said "Well I need you to prove to me that you're better than 9 other companies." For some reason he kept talking and eventually went to "Can I give you some advice?" I said "Look man, I'm not too sure why we're still talking honestly. I want to be honest, I think at this point it's pretty clear you don't want me to work for you and I don't want to work for you either." He said "You don't want to work for me?" Apparently he couldn't even tell that he had gone so far over the line that I confronted him, something I had never done in an interiew in my entire career before.
"Nooo," I chuckled. In the end, I'm glad I only had this awful experience when I was 30, because if I had been new to engineering at the time I might have blamed myself.