Having the ability to empathize with your customer is a powerful tool. If you can understand what motivates them you can use this information to better design a project and protocol that works best for everybody. Happy customers produce happy endings and we all like happy endings.
Many years ago some consternation developed on a project we were building. I trotted out the documentation to show why we did what we did. The customer told me that I did in fact do a great job of documenting but I had utterly failed to communicate.
His contention was that he was a smart, motivated guy and if there was a communication problem it was more likely on my end than on his. We write specifications and sign contracts all the time. Customers, for the most part, don't get much practice at this. It's our job to anticipate where the grey areas are and make sure that we illuminate them well.
Our customers have to make a million decisions about things they have never ever considered before. Many of these issues have to be magnified way out of proportion in to their significance (or context) later. When this happens it's easy to make every hill a hill to die on.
The customer needs to make informed decisions but you can't make them drink out of a fire hose either. Sean's gant chart does a good job of delineating milestones but it doesn't necessarily provide the kind of information to guide customers to the outcome we want to see.
The fortunate part of retail transactions is that the customer is highly motivated to get it right. They will happily consider any information you can put in front of them. In a world of Bert & Ernie's you have an opportunity to be Mr. Rogers.
Managing customers is truly a low volume-high mix operation. Even Taichi himself would tell you this is exactly the kind of work you need to get good at.