The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong

The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair. - Douglas Adams Not only would handling every case listed be time-consuming and introduce other problems, it wouldn't be good enough. Given enough time and users, a system that needs to take and honor 'open' inputs like names will eventually hit a case it can't handle, no matter much work went into flexibility. When it does, the question that matters is whether it fails elegantly and offers some kind of usable support. Being aware of common edge cases is important to avoid getting stuck in a design that can't fail gracefully. Covering edge cases is still good, not least because cutting the amount of support you need to offer makes more time to do support well. But I hope people aren't reading these lists and concluding that the fix is to be sure they support everything on the list.