tl;dr:"You know you can build a platform for monkeys to stand on. Plenty exist. You know you can build a flaming hoop for them to jump through. Plenty exist. You even know you can get a monkey. But can you train the monkey to jump through the hoop? Without the trained monkey, you have no spectacle. Nobody's gonna come watch a bunch of monkeys standing around a fire."
tl;dr:This post discusses: (1) The difference between engineering and programming. (2) Hyrum's Law - "all observable behaviors of your system will be depended on by somebody" so write tests on the code you like. (3) The earlier you find a mistake, the easier it is to fix, and more.