While there's no right (or wrong) answer to this question, it's important to be honest, positive, and specific. Even if your expectations weren't met, try to mention something positive you've gained from the position. It's important not to be negative, because that would make the interviewer wonder how you would talk about their company if you were hired. When asked what you expect from your next job, focus on what you have to offer the company.
Tell the interviewer that you have a lot to offer the organization, that your next employer will recognize your aptitude and put your skills to use. Describe one or two skills or areas in which you show promise and connect them to the job you're interviewing for. My expectations for my previous work were to teach my students a completely new English curriculum for the eighth grade that I would have to develop myself, but that would have the support of an adjunct teacher in all my classes. For example, this question can be phrased as “what are your expectations from the new job and the company” or “what are your professional expectations in the company in the next three years”.
It makes sense to review the standard set of questions and answers to help you better manage the job interview. In my previous job, my expectation, based on the job description and the interview, was that my job would involve working mainly on team projects. For example, if your job consisted of creating web applications, discuss the specific programs you developed and the responsibilities assigned to you. The interviewer will evaluate if the job was right for you and your career path in order to assess if you are suitable for the position you are hiring for.
If you applied to the company because you learned of its commitment to professional development, explain it when answering questions about your next job. One of the expectations I had for my previous job was that I would have the opportunity as an administrative assistant to take on a variety of leadership roles. Think about the type of expectations you have for this job and connect them to the expectations of your previous job. However, you should focus on the work itself, not on the company, your boss, or your co-workers (if they were a problem).
And, as you prepare for the interview, look for several ways to answer this question, depending on the direction you think the interviewer is taking to determine if you're a good fit for the company and the position.