"Better opportunity"
"Relocation"
"No room for growth"
are the top 3 things I would say.
I'm on the fence with "no room for growth", it's fine really but it sounds just a little negative to me. But I do understand the thought and reasoning behind the suggestion. It's often the truth!! But it seems to be that you don't leave just because there's no room for growth -- there has got to be a better opportunity to prompt you to leave.
I was stuck in a dead-end shit job for 3 years, where there was no room for growth whatsoever. I was actually LOSING money working that that hole, but not nearly as much as if I'd just up and quit because I couldn't advance myself at all. And that is indeed the reason why I left -- no room for growth -- but I only left once I found a better opportunity
