This may work in retail sales on low cost items. In process industry products and consulting you better figure out what they need and NOT just give them what they say they want (if it is something different). Otherwise it will be a one-time sale. That one-time customer will tell 9 other potential customers at the next convention that they had a short-term sense of euphoria with your product, but in the end a negative ROI.

Over the years I've seen many competitors wither and die following the "give them what they want and not what they need" mantra.