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
The superficial aspects of what someone else is doing What keeps me busy in my classes is trying to help my students learn how to think. They say, "Rob holds his hands like this...," and they don't know that the reason I hold my hands like this is not to make myself look that way. The end result is not to hold the gun that way; holding the gun that way is the end result of doing something else. …The more general issue is that a person who doesn't understand the thing they're trying to copy will end up copying unimportant superficial aspects of what somebody else is doing and miss the fundamentals that drive the superficial aspects. This even happens when there are very detailed instructions. Although watching what other people do can accelerate learning, especially for beginners who have no idea what to do, there isn't a shortcut to understanding something deeply enough to facilitate doing it well that can be summed up in simple rules, like "omit needless words". Dan Luu, Some thoughts on writing The Elements of Style style