The traditional approach to system development is often described as the Waterfall Model, which is a series of sequential steps that makes sense at first glance. Unfortunately, it doesn't work in practice (let me say that again: as a general rule, it does NOT work).
In fact, the first documented description of the Waterfall is from a 1970 paper by Royce, in which he describes it as a failed, broken approach that people should not use. Naturally, it's been widely adopted. Despite frequently disastrous results, people still talk about it as if it was a best practice.
I put together this little sketch for the 13 Theta comic series but decided to post it here instead.