Money is a fundamental tool of life!

Say you have a beautiful picture to hang on your wall, and having this picture up would make you happy. You need the tools to hang this picture on the wall - ie a hammer and nail. A hammer and a nail might not make you happy, but having them will enable you to hang your picture up - which will make you happy.

Hmmm, not a great analogy, but it's the first one that popped into my mind. :)