Although your brain is not a muscle, it helps to think of it as a separate entity that requires both food and exercise to make maximum use of its potential.
The exercise would include problem solving and activities which require thought and analysis. Food is information you take in, whether its through TV, radio, books, blogs, magazines, newspapers, or classes.
I've heard many people say that they hated school and have no desire to return to a classroom or write a paper again. Even so, in order to grow and to strive for your goals, you have to be continuously learning. Even someone in a "secure" position has to keep abreast of new developments in their area of expertise. Would you want a doctor who isn't aware of the latest treatments? Would you want a financial advisor who is clueless about market trends?
I am a practical person. My favorite book is a "how to" or self improvement. However, as a writer, I've learned that just reading other books helps develop my vocabulary and my voice. Your tool for learning may not be obvious. Classes and degrees are great and may be necessary for promotion or a career change. However, there are seminars, books, e-reports, and a host of other tools.
What do you want to be when you grow up? What is it going to take to get there? How can you find out? Sites like Career Builder and Monster can give you information. People who work in those fields are usually glad to share their story. Do some research and make a plan. You can achieve your dreams.