Explaining a layoff without sounding bitter - any advice?

They always ask why I left, and I freeze. I have been trying to stay organised about it. I have been practising in the mirror. What do you say?

Thanks for writing this out. I went through something close to it last year, and it settled down once I kept a simple log of every call and form.

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