Dev Desktop, WAMP, and MAMP are trusty tools in your Drupal toolkit. The more projects you take on, the more of a headache they become: conflicting versions of PHP, modules, configuration, and where in the heck did I put that INI file!? You're here to get work done, not headdesk because you've got the wrong version of Drush!
What if you could build a custom server environment for each project, using only a few text files? What if you could share those files in your repo so everyone on your team uses the exact same environment? You can!