Premature optimization is the root of all evil in programming.
You cannot teach beginners top-down programming, because they don't know which end is up.
Inside every large program is a small program struggling to get out.
I call it my billion-dollar mistake. It was the invention of the null reference in 1965.
Programmers are always surrounded by complexity; we cannot avoid it.... If our basic tool, the language in which we design and code our programs, is also complicated, the language itself becomes part of the problem rather than part of its solution.
I couldn't resist the temptation to put in a null reference, simply because it was so easy to implement. This has led to innumerable errors, vulnerabilities, and system crashes, which have probably caused a billion dollars of pain and damage in the last forty years.