Never stop learning, because life never stops teaching.
In order for us to be the best person that we can be it is imperative that we seek knowledge. With the use of technologies today such as books and the internet there is pretty much nothing on this world that we can not learn about with a little bit of research. Many faiths teach us that seeking knowledge is a huge key to being successful in this lifetime, and without it we limit ourselves greatly. Sure you may know a few things, things that will help you just coast through life. Why be good, when you can be great?
Our thirst for knowledge and more knowledge should never be filled, because there is always something or some culture that you dont know. Immerse yourself in books, or even better if you can immerse yourself in other ways of life, to get broader perspectives and gain the wisdom of many nations.