As a consultant in the customer service arena, you will be considered to be an expert on customer experience and customer satisfaction to the clients that you work with. While this question is certainly open ended, your interviewer is looking to hear that you have passion and belief in your answer because there is indeed no right or wrong answer to this question. Be sure to prepare for your interview ahead of time and be able to speak openly and passionately about what you believe is the most important factor for a satisfied customer.