Q: People always say that good style is important, but when they go out of their way to use clear techniques and make their programs readable, they seem to end up with less efficient programs. Since efficiency is so important, isn't it necessary to sacrifice some style and readability?
A: It's true that grossly inefficient programs are a problem, but the blind zeal with which many programmers often chase efficiency is also a problem. Cumbersome, obscure programming tricks not only destroy readability and maintainability, but they may actually lead to slimmer long-term efficiency improvements than would more appropriate design or algorithm choices. With care, it is possible to design code which is both clean and efficient.
See also question 20.13.