title: Remove elements from one List<T> that are found in another
body: <p>I have two lists</p>
  
  <pre><code> List&lt;T&gt; list1 = new List&lt;T&gt;();
   List&lt;T&gt; list2 = new List&lt;T&gt;();
  </code></pre>
  
  <p>I want remove all elements from list1, which also exist in list2. Of course I can loop through the first loop looking for each element in list2, but I am looking for elegant solution.</p>
  
  <p>Thanks!</p>