The discussion of abstraction in section 1.3.1 noted that one does not need to understand the makeup of the components as long as "everything about the detail is just fine." the case was made that when everything is not fine, one must be able to deconstruct the components, or be at the mercy of the abstractions. in the taxi example, suppose you did not understand the component, that is, you had no clue how to get to the airport. using the notion of abstraction, you simply tell the driver, "take me to the airport." explain when this is a productivity enhancer, and when it could result in very negative consequences.