What Is The Purpose Of Money?

Money. We all use it, want it, dream about it, worry about it, spend it, save it, and trade portions of our life for it. We judge our place in society on how much we have, and rank our country based on how much each member possesses.

But how often do we actually think about what it is for, and why it is so important in our lives? What is the purpose of money?

Related questions: How are money and value related? How should we compare each other? Why are we greedy?