What do I say about why I left my last job?

I have an interview next week and I am unsure how to explain why I left my last job as a barista. There are 5 people counting on me, so I am trying to be careful. I also do not want to seem like a risk. What do you say?

Practise it out loud with a friend. Mine felt natural after the third try.

Thanks for writing this out. I went through something close to it 8 months ago, and it got easier once I kept a simple log of every call and form.