title: TIMESTAMP vs TIMESTAMPTZ correct value when taking time difference
body: <p>For the query:</p>
  
  <pre><code>SELECT '2018-03-01'::TIMESTAMP - '2018-09-01'::TIMESTAMP, 
         '2018-03-01'::TIMESTAMPTZ - '2018-09-01'::TIMESTAMPTZ;
  </code></pre>
  
  <p>the values <code>-184 days</code> for <code>TIMESTAMP</code> and <code>-183 days -23:00:00</code> for <code>TIMESTAMPTZ</code> is returned.</p>
  
  <p>To me, <code>-184 days</code> "seems" correct but I was always told to use <code>TIMESTAMPTZ</code>. Which is the correct answer?</p>