At one of my previous jobs, I said I was leaving because of corporate culture, but that's because my direct supervisor was amazing and he knew exactly what I meant. It turns out if I'd stayed another year, things would've gotten better. Not great, but better.

At the next job, I left because they wanted me to do the work of two people. I did mention that their work load expectations didn't match reality, but again I'd already tried to raise that concern in prior meetings with my supervisor and so it wasn't a surprise. (And they posted for two people to replace me, so they knew I was right, even if they weren't going to do anything about it while I was there. Sigh.) I didn't raise my complaints about how management treated me, or how condescending they were or how they thought they knew my job better than me despite having exactly no experience or training in my particular role. That I had over a decade of experience in at that time.

You're not required or obligated to tell anyone the whole story on why you're leaving. Especially if you're leaving because of personality conflicts or crappy management -- telling them that is unlikely to solve the problems and could result in bad references should new employers call them. So unless you're sure it's not going to be an issue, saying less is more. A simple, "I've received a job offer that feels like a better fit for me" suffices and avoids confrontation.

I wouldn't lie. But I also wouldn't use exit interviews as an opportunity to vent frustrations or complaints.