In behavioral interviewing, a candidate is asked about his/her response in a past situation. The theory is that past behavior will predict future actions.
Practicing how to answer behavioral interview questions will make you more comfortable and more adept when addressing them.
Employers usually think first about behaviors that are needed in the open position, and based on that develop questions to elicit responses that might demonstrate the candidate's performance in those areas. Some examples of behaviors employers might want to know about are: flexibility, independent thinking, presentation and listening skills, planning ability, team participation, attention to detail, handling change, professionalism, and dealing with frustration. The interviewer will typically ask questions that start off sounding like an opportunity to converse or to share about yourself.