There has been much discussion of late in Drupal about Object-Oriented Programming. That's not really surprising, given that Drupal 7 is the first version that has really tried to use objects in any meaningful way (vis, as something other than arrays that pass strangely). However, too much of the discussion has boiled down to "OMG objects are inflexible so they're evil!" vs. "OMG objects are cool, yay!" Both positions are harmfully naive.
It is important for us to take a step back and examine why one...