In marketing, it pays to remember that emotion sells. People aren't cold and rational actors on a commercial stage. They make most of their decisions based on emotion. Even Alan Greenspan had to finally admit that regarding the stock market when it was clear that greed pushed the global financial system over a precipice.

Even as you trot out your list of customer benefits, it's possible to miss the forest for the trees. People not only purchase products, but they buy experiences. For an example, look at this Marketplace piece on comparative shopping.

It's easy to compare prices on some types of products and services. Airline tickets are a great example. You can also expect to have a good idea of what various places charge for a sack of sugar or a dozen eggs. But for many types of products, the comparison choices are slimmer (although not non-existent as Marketplace seems to argue).

Too much information can decrease the chance someone will buy. It's too tiring for most people to go through all the data. Retailers similarly want to avoid too much transparency, as it can lead to industry-wide patterns of price deterioration.

But, as importantly, there is a psychological aspect.

"When there's something I've been eyeing and I see it go on sale, it's like God just sort of put it there for me," said Elise Ariel, a 37-year-old legal assistant, as she shopped recently at Century 21 in Manhattan. "How do I feel about sales? Like a moth to a flame."

I've heard related observations from marketing experts over the years. Many people like the sense of winning a contest by getting a lower-than-expected price.

Psychology extends beyond scoring a good deal. Upscale department store chain Neiman Marcus doesn't worry about cut-rate prices. Its customers are interested in a pampered and indulging shopping experience. The chain has top merchandise and storied customer service.

Every customer has at least an emotional component to his or her decision. Smart business means understanding the emotional needs of customers and then catering to those as well as the practical considerations. You always want to market and sell to the entire person, not just one part. That's the way to initial sales, continued relationships, and customer loyalty.