A succinct way I’ve framed the split is that a front-of-the-front-end developer determines the look and feel of a button, while a back-of-the-front-end developer determines what happens when that button is clicked.
Doing it right requires a different pace of working and a much broader thought process than “ok, let’s get this thing out the door.” Which is super tough because most workplaces place a huge emphasis on getting things out the door, and fast. Little agile tickets that are expected to be completed in micro sprints to me seem to be antithetical to doing it right.
This sounds like a paradox, but a great painting has to be better than it has to be. For example, when Leonardo painted the portrait of Ginevra de Benci in the National Gallery, he put a juniper bush behind her head. In it he carefully painted each individual leaf. Many painters might have thought, this is just something to put in the background to frame her head. No one will look that closely at it.
Not Leonardo. How hard he worked on part of a painting didn't depend at all on how closely he expected anyone to look at it. He was like Michael Jordan. Relentless.
Relentlessness wins because, in the aggregate, unseen details become visible. When people walk by the portrait of Ginevra de Benci, their attention is often immediately arrested by it, even before they look at the label and notice that it says Leonardo da Vinci. All those unseen details combine to produce something that's just stunning, like a thousand barely audible voices all singing in tune.
Great software, likewise, requires a fanatical devotion to beauty. If you look inside good software, you find that parts no one is ever supposed to see are beautiful too.