
Deliverables must be usable. If the customer is provided 400 pages of word documents and a dozen spreadsheets, the customer often asks what did I get for my investment of time and money? Building solutions is an interactive process. Each step is an iterative exercise in marketing and prototyping. The first iterative layer is the customer's management. The second layer is your team. The thrid layer includes your customers and suppliers.
For different reasons and motivations, each is a stakeholder. Each can challenge the effort. Through interactive design sessions, prototyping, market research, project plan development and budgeting, the entire team has the opportunity to participate in a new vision. With everyone expressing their interest in the solution, the 80% rule has a much better chance of succeeding.
Surpisingly, it is often the business owners or the subject matter experts who have been with the organization the longest (often the same group) who require the most convincing and hand holding.