The competent programmer is fully aware of the strictly limited size of his own skull; therefore he approaches the programming task in full humility, and among other things he avoids clever tricks like the plague.

Simplicity is prerequisite for reliability.

There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult.

say again and say often: complexity very, very bad

Simplicity is the best strategy for scaling. When engineers think about how to solve a complex problem, the obvious answer is to design a complex solution, one with good asymptotics but high fixed overheads. If instead you look for ways to simplify the problem, that often leads to simple solutions with low overheads that work just as well. Simpler solutions scale better and are easier to maintain.