This is without a doubt a sales truism. You actually are perceived as what your customer believes you are. Yes, I know it sounds confusing however I'm trying to write this thinking about how you currently perceive me; even more confusing. Unbelievable in the first paragraph I'm already running down another rabbit trail. Sorry.
The point I really want to drive home is that how you handle every aspect of your sales call is being directly compared to every other sales person who has been before you. So it is not your product, it is not your market, it is not your demonstration, power point presentation or even your aunt Roses' secret death by chocolate brownies that you brought to your customer. (Although if they don't care for the brownies that sure is a great excuse for why you didn't close the sale.)