The best way to respond is to discuss what your expectations were when you took the job, and give examples of how the position worked out for you. If the job wasn’t exactly what you expected, it’s fine to mention that. However, you should focus on the job itself, not the company, your boss, or your colleagues (if they were a problem). Be careful how you answer and don’t focus too much on the negative. Instead, address the highlights of the job.
When responding, be specific. Prepare some examples to share with the interviewer in advance. For example, if your job involved creating Web applications, discuss the specific programs you developed and the responsibilities you were given. If you were provided training and opportunities for professional development to help you achieve your goals, mention that as well.