One of the significant improvements of Drupal 8 that got me excited was the services & dependency-injection throughout the entire Drupal system. From aspects like routing, templating, managing configuration, querying and persisting data, you name it everything is done with services. it's fantastic because it grants developers a level of flexibility in extending Drupal that is far greater than what Drupal 7 was able to. by using well-disposed structure developers get ride of ravioli coding.