title: What are the Ruby Gotchas a newbie should be warned about?
body: <p>I have recently learned the Ruby programming language, and all in all it is a good language.  But I was quite surprised to see that it was not as simple as I had expected.  More precisely, the "rule of least-surprise" did not seem very respected to me (of course this is quite subjective).  For example:</p>
  
  <pre><code>x = true and false
  puts x  # displays true!
  </code></pre>
  
  <p>and the famous:</p>
  
  <pre><code>puts "zero is true!" if 0  # zero is true!
  </code></pre>
  
  <p>What are the other "Gotchas" you would warn a Ruby newbie about?</p>