>I only need simple one.

The best reason is the way objects can interact with other objects.

In VFP7 you can:
1. Set properties of an object
2. Execute methods on an object

In VFP8 you can:
1. Set properties of an object
2. Execute methods on an object
3. Raise an exception from an object
4. Raise an event from an object

With VFP8, you can really create better OO systems. Period.

Simple enough? :-)