What do I say about why I left my last job?, bookkeeper here

They always ask why I left, and I freeze. I would rather hear the honest version than the polite one. I have been practising in the mirror. Do they ask follow-ups?

Say it plainly and move on to what you can do. Interviewers usually move on if you do.

If a company has been in the news for layoffs, you can mention that. Often the interviewer already knows.