I suppose there's an exception to the rule: when I'm seeking out a product that I already intended to buy, I'm not above using the salesman as an expert on his own product line. That usually goes pretty well.
But man, when the unwanted upsell starts . . . I politely say no, but I'm sure you'd be able to tell from my demeanor that I feel quite insulted.
But man, when the unwanted upsell starts . . . I politely say no, but I'm sure you'd be able to tell from my demeanor that I feel quite insulted.