It is unfortunate, but true: for many teams error handling is an afterthought. They design the main flows of their system and then they think about where they need exceptions and logging. However, the error cases are extremely important. When we consider them along with the normal cases, we an often find ways to arrive at better design. In this workshop, we will pursue design a series of solutions to the same problem with the error cases considered early and late. Then we will compare and contrast solutions and see how early consideration of cases can affect the growth of a design.