If the Interviewer Mentions Pair Programming
Time to go

Edit 9/27/2020: since I wrote this, pair programming has abruptly all but vanished from the industry. Apparently enough people hate it as much as I do and there have been protests and resignations. It still has its advocates who claim it’s useful but it’s drawing to a close, and good riddance.
You’re in a software development interview. Maybe you’ve already had a red flag or two (agile, scrum, TDD), maybe it’s looking good. You have not yet been told to write some hyperoptimized algorithms for things like linked lists or binary trees that nobody uses anymore.
Then the interviewer says something about pair programming.
Unless it’s in the context of “we don’t do that here,” you should
- pick up your things and walk out
- do not say “thank you for your time”
- do not respond to his “where are you going?”
- do not give him a middle finger; do not acknowledge him further in any way
Just leave. Find a job not managed by sadists.
Pair programming is monstrously unacceptable and contrary to everything we know about software development productivity. Moreover, unless your partner in pairing is someone you are intimate with, the experience can be so excruciatingly uncomfortable that you find yourself with PTSD, even after a single session.
Mentoring is better done in something closer to a tutoring or classroom session; a code walkthrough doesn’t require sitting in near-sexual proximity nor sharing a computer. You scroll, your partner watches. Same for design collaboration, which might be done in similar conditions.
But the idea behind pair programming, actually trying to produce code, is simply vile and our response to it should be unequivocal resistance. Don’t let some manager put you in the hospital because he believes in this ridiculous fad.