What is the meaning of good education?

How does one define good education? How much good makes it good? How can you differentiate between good and bad education? And most importantly, why is it important?
Anything that enhances the mental capacity of a person and makes one more liberal had acquired good education. Liberal here means one who is willing to listen to new ideas and accepts them if they are any good. An increase from 1 to 2 is an increase of 100% but an increase from 10 to 11 is an increase of 10%. Although knowledge has no limits and no matter how much one knows, it is always a fraction of the total knowledge in that specific area let alone the universe of knowledge. Raising a person who knows nothing at all to a somewhat easy to achieve and that is what should be the focus on. Creating minds that have the capacity to observe, think and act is very important to make the best out of the population and achieve the highest levels of gross domestic product.