I think a lot of interviews are a waste of time! I have no idea why interviewers don't just do the obvious ...
I went to one interview and was not asked a single question about electronic design or software development, which were the two areas that I would be working in. When it came to the end of the interview I asked why they hadn't checked my technical ability. The response was that they trusted the university exam system to weed out the incompetent ... Ha ha, that's all I can say about that - exam systems simply weed out people who can't pass exams!
For example - at university, I helped one of my fellow undergraduates with a problematic circuit that he was working on. He kept saying that it must work, he had double-checked his calculations. I pointed out that he would have needed to use a power supply with more oomph than the National Grid to do what he was trying to do! On top of which, the components he was using were not capable of working at the frequencies involved. And so on ... This lad had passed all of his first year exams, and was halfway through the second year of an Honours degree.
Years back, we got a new programmer straight from university. I spotted him looking very furtive, and discovered that he was balancing a copy of
K&R on his lap, under his desk. I had a quiet word with him while management were looking the other way ...
We needed an experienced C programmer, so the company had advertised for one. New Guy had gone to his interview and just blagged it. They asked if he was experienced, so he simply said
'Yes' and they took his word for it!
It isn't difficult to check if somebody knows C. There are some incredibly easy traps to fall into which any experienced C programmer would know about. You could show them some suitable sample C code and ask them what it was supposed to do, and what was wrong with it. Nope, didn't bother. They probably asked him where he saw himself being in 5 years time. In reality, that was as a software team leader -
somewhere else!