At DrupalCon Baltimore, I presented a Single Sign-On (SSO) example module illustrating how object oriented programming makes Drupal 8 modules easier to code, understand and debug.
The website developed for the presentation uses OpenID to allow users to login using their social media credentials. Although the OAuth 2 and OpenID protocols are explained, the main focus of the session is to demonstrate how object oriented programming has replaced hooks for extending Drupal, and describe how to use plugins, event listeners, route subscribers and other tools.
It also (hopefully) helps us understand how to examine other modules and find ways to extend their functionality.
View the slides, the example module code and the video of my session (below).