What are some things that only someone who has been programming 20-50 years would know?

Everything in software development has already been invented. People just keep rediscovering it and pretending they invented it. Whatever you think is so cool and new, was copied from Smalltalk, or HAKMEM, or Ivan Sutherland, or Douglas Engelbart, or early IBM, or maybe Bell Labs.

No matter how many managers are screaming at you, the first step is to reliably replicate the bug.

And other gems… great short little read.