That Yamaha that just cut you off is an instance of class Motorcycle, which is a subclass of MotorVehicle. Its rider is an instance of class Jerk, which a subclass of class Person. And so on. As you've learned, objects are grouped into classes that share common methods. This sharing is called inheritance.
Inheritance greatly reduces the amount of code needed to run a program successfully.
Once a method is created in a class, it can be used by that class and all its subclasses. In other words, the code is written once, not every time a similar object needs it. For example, every instance of superclass MotorVehicle knows how to go faster, how to turn, etc. The subclass Convertible knows how to do everything that class Automobile does, plus it knows how to lower its fabric roof. Every instance of class Person knows how to eat lunch, go to sleep, etc.