If there's only one answer, then this must not be a very interesting topic..

One of the great skills in using any language is knowing what not to use, what not to say. There's that simplicity thing again..

The wages of sin is debugging..

Simple, not easy. There's a difference..

The lesson is: Even if you know exactly what is going on in you system, measure performance, don't speculate. You'll learn something, and nine times ….

When we use a language, we should commit ourselves to knowing it, being able to read it, and writing it idiomatically..

Three bloody roles, Scrum has, and only three. If you can’t get that right, don’t call it Scrum, OK?.

Code never lies, comments sometimes do..

It seems to me to be important to distinguish a good idea from poor implementations of it.