This happens in Germany.
Work culture doesn’t fit my personality: I don’t talk much, I keep to myself, I simply want to do my job and go home, I separate my personal life from work, my colleagues are full fledged gossips, ignore the duties that need to be done and then expect me to help them when they are late. I don’t have patience for that crap anymore.
Due to internal regulations, I have to stay on the unit for 4 weeks after sending my notice. Answering honestly the question of why I’m quitting would ensure that they yell at me and bully me, and I don’t want to experience that again. Even saying ‘it’s none of your business’ ensures that they feel insulted and start yelling. I have decided I don’t have patience for people like that anymore.
So, what do I say?
Is “going back to school” a thing in Germany? From what I know about that education system I’m guessing not, but in the US that’s a standard answer.
“I want to move to be closer to my aging parents.” - might work. If you haven’t shared much about your life, it’s an easy lie. And it’s dull and depressing, so the odds of followup questions are slim. I hear it a lot when interviewing job candidates in our area.