The goal of Lean is to deliver increased value to the customer through eliminating wasteful processes. When one talks about waste in this sense, often they refer to the seven wastes in manufacturing or Muda from the 3M model. Mura and Muri are often excluded from the picture but knowing these two is crucial as they are more likely to have caused Muda to appear in the first place. A good understanding of all three will surely help any business in streamlining their processes.