Personally, I find that taking a very aggressive approach to the Liskov substitution principle is the most helpful rule of thumb. I follow it to the point of pr

Personally, I find that taking a very aggressive approach to the Liskov substitution principle is the most helpful rule of thumb. I follow it to the point of practically never using inheritance. If you are using inheritance to modify behavior, then you are probably ignoring LSP and making your code "unintelligible".