Use of the comma is not appropriate in your case. The serial comma is used only when there are three or more items in the series.
It's appropriate to use a serial comma in:
Chicago, London, and New York are major financial hubs.
It's not appropriate to use a serial comma in:
Chicago, and London are major financial hubs.
In your case, you only have two items that are joined by conjunction. The serial comma is not appropriate there.
It would be appropriate to use a serial comma in your example had your sentence been:
You can't predict how people are going to react, or what's going to happen, so just make your move, and then observe, don't react, and appreciate what happens.