Designer, implementor, user, writer A Fragment by Donald Knuth dl.acm.org Thus, I came to the conclusion that the designer of a new system must not only be the implementor and the first large-scale user; the designer should also write the first user manual. The separation of any of these four components would have hurt TeX significantly. If I had not participated fully in all these activities, literally hundreds of improvements would never have been made, because I would never have thought of them or perceived why they were important. Eating your own dog food making
You'll know it's there Jobs's father had once taught him that a drive for perfection meant caring about the craftsmanship even of the parts unseen. Jobs applied that to the layout of the circuit board inside the Apple II. He rejected the initial design because the lines were not straight enough. In an interview a few years later, after the Macintosh came out, Jobs again reiterated that lesson from his father: "When you're a carpenter making a beautiful chest of drawers, you're not going to use a piece of plywood on the back, even though it faces the wall and nobody will ever see it. You'll know it's there, so you're going to use a beautiful piece of wood on the back. For you to sleep well at night, the aesthetic, the quality, has to be carried all the way through." Walter Isaacson, Steve Jobs All the way through craftquality