We optimize what we measure Scrum does not say “only focus on output”, but, unfortunately, humans will optimize for what they measure. If you worry about story points & hitting your estimations, that’s what is going to consume your attention. That is what you and your team will optimize for. And that is the core critique of Scrum as it is practiced: That it focuses a product team’s attention so heavily on delivery — on building lots of features quickly & efficiently — that teams fail to focus on spending time to discover what the right thing to build is. Henry Latham, Why Scrum is killing your product optimizationagilefeatures
Essential vs. nice to have Customers have trouble distinguishing between essential features and those that are just "nice to have." Examples of the latter class: those arbitrarily overlapping windows suggested by the uncritically but widely adopted desktop metaphor; and fancy icons decorating the screen display, such as antique mailboxes and garbage cans that are further enhanced by the visible movement of selected items toward their ultimate destination. These details are cute but not essential, and they have a hidden cost. / Increased complexity results in large part from our recent penchant for friendly user interaction. I've already mentioned windows and icons; color, gray-scales, shadows, pop-ups, pictures, and all kinds of gadgets can easily be added. Niklaus Wirth, A Plea for Lean Software Menus, Metaphors and Materials: Milestones of User Interface Designlittlebigdetails interfacesux