Third of all, not only they are our example but also they give us responsibility about life. While you're at home usually your mom can want you to help her for cleaning or cooking. Your father can need your help to repair some things at home. or they can want you to organize and clean up your room. This experiences will lead you to help people, to share their responsibility and learn how to leave all together in one house. This is important because you can not learn this knowledge at school. Only you can learn it from your family.
In conclusion, the reasons I mentioned above I totally agree that parents are the best teacher. They create your path and they're the most important person in people's life. If they can educate their children well they can be really successful because they let children to face the real world. They can encourage and teach children to become a good human.