I've never had a truly horrific interview.
The closest was the one where I stopped after 5 minutes and said "I'm really sorry, but to save wasting anyone's time, I've realised that I don't think I'd be happy working here".

I meant it genuinely to save us all time and effort, but you'd have thought I'd shat on the table by the look on their faces.
( scarpe We Stole Bikes, Tue 5 Feb 2013, 8:57, 2 replies, latest was 13 years ago)

Frankly, you get points for that
I can think of one job I had - for about a week - whereby I'd have saved myself a week of abject misery had I taken a similar attitude in the interview.
(Darth Foxtrot A one-man army dedicated to making fetch happen, Tue 5 Feb 2013, 8:59, Reply)

I did the reverse
went for a job I didn't think I'd like much or get, realised mid interview that I really wanted it after all, said so and got the job.
( CQ Knows the truth, all of it., Tue 5 Feb 2013, 9:51, Reply)