John Carmack on Functional Programming

Two quotes here that are really good:

A large fraction of the flaws in software development are due to programmers not fully understanding all the possible states their code may execute in.

No matter what language you work in, programming in a functional style provides benefits. You should do it whenever it is convenient, and you should think hard about the decision when it isn't convenient

It's from 2012, should be in the title. Good read though.