I view OO as analogous to the earliest control structures added to programming languages. We all remember "GOTO considered harmful", including generations of pr

I view OO as analogous to the earliest control structures added to programming languages. We all remember "GOTO considered harmful", including generations of programmers who weren't alive when the letter was written, and may not have read it. Around that time, language designers realized that GOTOs were used to implement the same patterns over and over: Conditional execution, looping of various kinds. And we ended up with if statements, while loops, for loops, and so on. Similarly, unfettered access to state was seen to be problematic. If you are implementing a skiplist, you don't want users of the list to be manipulating the links directly. You want to expose only the operations, and have the state accessible only to the implementation. That's encapsulation and modularization. And then inheritance provides a way to modify modularization slightly. OO is really just a few ideas about organizing code and data, and you are free to use them or not, just as you are still free to use gotos. The hype got out of hand. I think OO madness was the first vastly overhyped software trend. Things got bad with all the Janitor ISA Employee examples got trotted out to explain OO to managers, and then some people believed OO was claiming to excuse programmers from actually developing efficient code. Anyone using, say, Java to build a complex software system realizes that OO is used to model internal things that never get anywhere near a customer-facing API. There were zealots, there were AbstractFactoryFactoryAdapterFactory nuts, and the backlash against them is totally justified. But the core ideas of OO are just obviously good ones, and usable in non-OO languages too.