Why did you leave your last job?

(This is not an opening to speak badly of your former employer. There is almost always a way of wording the explanation so that you do not sound like a "problem employee" and your former employer does not sound like an undesirable company.) As unfair as it may seem, there is almost no time when you should say something bad about your former employer. You can talk about the lack of potential for upward mobility, the fact that your job responsibilities changed to the point that it no longer fit into your career plan, your need to move to be closer to your aging parents, the need to reduce travel time, your need for a more challenging job, or anything else that does not get into personalities or other conflicts. If you were fired for cause, you may want to be up front about it, explain the circumstances and accept responsibility for your actions. Practice your answers to this question with someone who has interview experience. However, don't lie. If you can't say anything positive about your former employer, don't say anything. It could come back to haunt you.