Do you go through the whole process? I never know if I should just bow out in the middle if I they've scared me off. Just say I think I can save us both our afternoon.
The alternative is to try to keep up the pretense and I'm terrible at that, so I end up sandbagging the interview and then they of course don't make an offer. And no matter how many times I look at it, I can't decide which is less likely to cause me problems in the long term.