title: Applicative Functors and Left from Either
body: <p>I have been working through the <a href="http://learnyouahaskell.com" rel="nofollow">great good</a> book, but I am struggling slightly with Applicative Functors.</p>
  
  <p>In the following example <code>max</code> is applied to the contents of the two Maybe functors and returns <code>Just 6</code>.</p>
  
  <pre><code>max &lt;$&gt; Just 3 &lt;*&gt; Just 6
  </code></pre>
  
  <p>Why in the following example is <code>Left "Hello"</code> returned instead of the contents of the Either functors: <code>Left "Hello World"</code>?</p>
  
  <pre><code>(++) &lt;$&gt; Left "Hello" &lt;*&gt; Left " World"
  </code></pre>