When a product manager conducts an interview at a customer site, his purpose is not to sell the product or tell how it will benefit the customer. The purpose is to understand the customer's situation and problems, irrespective of whether the product solves them.
Consequently, there is no reason for the product manager to flaunt his knowledge of the market. In fact, claiming to know a lot about the market will tend to:
- Make the customer feel her ideas and perspectives aren't very important, thereby demotivating her during the interview.
- Cause the customer to omit information under the premise that the product manager knows it all anyway.
- Set expectations high, thereby increasing the chances the product manager will disappoint the customer.
When you're learning, plead ignorance, and do it confidently.