>I think this shows how difficult interpretations can be

It's not interpretation, really, I think. It speaks to the asymmetry of the situation and how, if you are the interviewer, you need to be thoughtful about what you say at all.

I learned this early on, much to my chagrin. An interviewee was obviously stuck and getting themselves in a muddle so I stopped them and redirected to a different question; I thought it was in a lighthearted manner and communicated that I wanted them to relax and regroup - found out later they felt I was making fun of them and had a terrible interview experience. Ever since then I've been much more careful and explicit.

What I thought was being considerate was read as being condescending, I suspect, even though my intent was pure the situation is fraught with potential for miscommunication.

It's difficult to know how best to react to interviewees being stuck. If you leave them stuck, they may take it badly; if you redirect them, they may take it as a sign that they "failed" this part of the interview.

I try to say something along the lines of "OK, I think it's time to move on to something else; in an interview situation, you sometimes go down a blind alley, but that does not really reflect on the real world, and I think I've seen enough to move on to the next subject."

The latter is similar to the approach I take also - but tellingly also what I thought I was saying in the situation related about. I'm more careful with language now.

Yes, and even if it _was_ in fact what you were saying, it may not have been the message that got through to them.

I have to agree, I would guess that the interviewer could tell the OP was nervous and was trying to lighten the mood a bit. Though, asking someone to write a language they don't use everyday is a pretty horrific thing to do in an interview. I've always been able to interview in my preferred language, even if the company didn't have one line of it in production.

Kidding around is kinda risky- it can easily come off as not taking you or your time seriously.

Treat people with respect seems to be uncommon common sense.