Object oriented programming - class design confusion

Question

I am trying to wrap my head around object oriented programming.

My understanding is that we have objects so we can design our programs to mirror real-life objects.

Answer 1

Something of class Herbivore would have an Eat function, as would something of class Carnivore, but each one's Eat would have some differing restrictions on what argument could be passed to the Eat function. The Fruit is what is eaten, so it would be passed as the argument to Herbivore.Eat(), whereas you would want to pass an object of type Hamburger to Carnivore.Eat(), and raise an exception if Hamburger were passed to Herbivore.Eat().

But really, I don't think OOP is so we can model software objects to be just like real-life objects. I've found that most of my OOP design works with pretty abstract objects, and only with respect to the system they are part of. If I wrote a library checkin/checkout system, I would model a Book in terms of its administrative properties and functions - I would not model it as a collection of Page objects, and I doubt I would even define anything like a Read() method, although such is the main purpose of having a book in the first place. The Book object's role in the system dictates my design much more than what one does with books in the real world.