Suppose. One company has finished a software project. The management values the results as very good. The firm sells many copies of the software. The customers are satisfied with the product. Everything seems to be OK. Of course the product has some problems. There are some errors in the software. The users will get some additional features. On the market come some new programs and the firm's program must be supplemented to support them. None of the problems seems to be dangerous.
The firm starts one new project to solve these small problems and produce the next version of the software. The second project goes not as well as the first, but nobody notices any danger. Only after missing of many deadlines and exceeding of budget management becomes the opinion that the second project goes not normal and simple changes are not simple. Sometimes it's too late. New version cannot be ready in the time it should be and the company loses its market share.