For example these classes are abstract Mage_Catalog_Model_Abstract,Mage_Core_Model_Abstract etc.But it contain only defined methods.and what is the necessity to given class as abstract.
I know abstract class how to declare and rules.But i need more real time example(like magento).
Even i deleted abstract keyword before class name.but its not giving any error.
thanks in advance


Question: How to formally state that parents have not raised their children well
Answer: 
  Irresponsible


This should fit the bill of describing the core issue, whilst not judging manners broadly, nor performing character assassinations.  

I think dysfunctional is also insufficient because functionalism can come under heavy debate.