All the Little Things by Sandi Metz

Theory tells us to build applications out of small, interchangeable objects but reality often supplies the exact opposite. Many apps contain huge classes of long methods and hair-raising conditionals; they’re hard to understand, difficult to reuse and costly to change. This talk takes an ugly section of conditional code and converts it into a few simple objects. It bridges the gap between OO theory and practice and teaches straightforward strategies that all can use to improve their code.