The first point of failure is typically misunderstanding the problem. If we don't understand what users are truly trying to accomplish, and we have not received all requirements, then we will inevitably retain a bad model of the problem and thus end up implementing the wrong solutions.

Imagine that this scenario occurs at some point before the invention of the kettle:

• Susanne (engineer): Matt, we've been asked to design a vessel that users can boil water with
• Matthew (engineer): Understood; I will create a vessel that does exactly that

Matthew asks no questions and immediately gets to work, excited at the prospect of putting his creativity to use. One day later he comes up with the following contraption:

We can see, quite obviously, that Matthew has forgotten one key component. In his haste, he did not stop to ask Susanne for more information about the user, or about their problem, and so did not consider the eventuality that a user would need to pick up the boiling-hot vessel somehow. After receiving feedback, naturally, he designed and introduced a handle to the kettle:

This needn't have occurred at all, though. Imagine this kettle scenario extrapolated to the complexity and length of a large software project spanning multiple months. Imagine the headaches and needless pain involved in such a misunderstanding. The key to designing a good solution to a problem requires, first and foremost, a correct and complete model of the problem. Without this, we'll fail before we even begin. This matters in the design of massive projects but also in the implementation of the smallest JavaScript utilities and components. In every line of code we write, in fact, we are utterly liable to failure if we do not first understand the problem domain.

The problem domain encapsulates not only the problem being encountered by the user but also the problem of meeting their needs via the technologies we have available. And so, the problem domain of writing JavaScript in the browser, for example, includes the complexity of HTTP, the browser object model, the DOM, CSS, and a litany of other details. A good JavaScript programmer has to be adept not only in these technologies but also in understanding new domains of problems encountered by their users.