And that's a lot of the reason why we care so much about our careers and indeed start caring so much about material goods. You know, we're often told that we live in very materialistic times, that we're all greedy people. I don't think we are particularly materialistic. I think we live in a society which has simply pegged certain emotional rewards to the acquisition of material goods. It's not the material goods we want;
The Liskov Substitution Principle is a fundamental concept in object-oriented programming, stating that objects of a superclass should be replaceable with objects of a subclass without affecting the correctness of the program.