It's pretty simple. In order for someone to remember you and your product, they must feel something when they interact with you. And, obviously, a good memory comes from positive feelings.
It's not good enough just to have "great service". It must be delivered in a personal and adaptive way to create emotion. So, the next time you need to make decisions about your product or service, ask yourself, "How will they feel?", i.e., rushed, comfortable, warm, betrayed....you get the picture.