A pattern I've noticed on a number of teams is that work-in-process piles up waiting for someone to "sign off" work items that are in a state such as "developer complete" or "done" (but not "done-done"). Usually, the team doesn't do anything about the problem. Developers continue to pump out code as fast as they can. The code continues to pile up as inventory in front of the "sign-off" step. As a result, the people responsible for the sign-off become stressed out and frustrated. Because developers don't slow down and pay more attention to detail, and because the sign-off people try to rush through the pile of inventory, the team pushes out more and more defects. The back-flow of defect reports grows and degrades the team's production rate. It's a vicious cycle.