Drupal: An Important Debugging PHP snippet while making forms

For long I have been trying to debug and create forms on Drupal and have been using "devel" module available on the Drupal site. But, this one is the code that has rescued my efforts many a times. So I thought of posting it here:

print "<div style=\"width:500px;\"><pre>";
print_r($form); // displays all the variables available
print "</pre></div>";