title: List.Find() issue
body: <p>I am wondering why I have this problem with my list.</p>
  
  <p>I am trying to retrieve the object for the previous index, so -1;</p>
  
  <p>Is that the good way to do ?</p>
  
  <pre><code>thePreviousList.Find(previousItem =&gt; previousItem.Id - 1);
  </code></pre>