Some people think that the if branch should be the every thing is good branch and the else branch being the error case. Others think the if branch should be as short as possible since it makes it easier to understand what would bring us into the else branch. But this rule is not about what guideline is the best. It is about putting you into a situation where you have to consider other ways to implement your conditional logic. Polymorphism and the Null Object pattern being two good alternatives.