Way back when I was first learning OOP, the typical "car extends vehicle" examples caused me not to see the practical point of OOP for a long time. I still resist using object-oriented approaches except in cases where the code demands it. (A feature, not a bug?) And, these days, if I do use OOP in places in the code, it's for encapsulation -- which is only a style consideration -- so the "car extends vehicle" example still doesn't apply.

I think a simple example from GUI programming would do much better. How about window classes? I did something like this recently:

    class Window {
        public method show()
        public method title(newTitle)
        public method close()
    }

Easy enough. What if I want a modal window though? Almost everything in it would be the same as a regular window, except I might need to do some things slightly different for show()ing and close()ing the window. Aha! A perfect example of an appropriate time to create a subclass:

    public class ModalWindow extends Window {
        public method show()
        public method close()
    }

Programming tends to attract practical individuals. I think teaching "car extends vehicle" then is usually going to cause one of two results: either a student that then uses that approach all the time, even in cases where it's not warranted, because they don't understand when it's appropriate and when it's not; or a pragmatic student that resists using it because the given examples don't apply to anything that they're actually going to have any chance of working on.