What makes to world go round

Of course, most will quote the song and say money.  But, no it's desire.  Money is just an embodiment of that desire and what we are willing to do to get it.  It becomes a symbol of determination and perseverance for each individual.  You can see it when you look at the pride in someones eyes.  they worked, they sacrificed, they went without in one area to have something in another.  Lack of sleep to study, lack of food to have tires, lack of interaction to work.  Money is just a symbol, you trade that symbol to get another.  We make idols of the desires we have.  We covet.  We lust.
So, what makes the world go round?  Gravity and interstellar interaction of course.  Because the world wants to go some where as well.