title: Lazily instantiated && Singletons in AngularJS?
body: <p>In <a href="https://docs.angularjs.org/guide/services" rel="nofollow noreferrer">AngularJS </a> docs, I read that AngularJS services are:</p>
  
  <blockquote>
    <p>Lazily instantiated – AngularJS only instantiates a service when an application component depends on it.</p>
    
    <p>Singletons – Each component dependent on a service gets a reference to the single instance generated by the service factory.</p>
  </blockquote>
  
  <p>What are these concepts exactly? I don't have any intuition about these subjects.</p>