Unnecessary commas?

Question

I was just writing this sentence:

You can't predict how people are going to react, or what's going to happen, so just make your move, and then observe, and appreciate what happens.

And I realised that the comma is unnecessary, one could write:

You can't predict how people are going to react, or what's going to happen, so just make your move, and then observe and appreciate what happens.

Is there any grammatical rule about whether a comma should be used here or not? Or is this more a stylistic thing?

Answer 1

Your comma is a serial comma, also nicknamed "oxford comma". In this case it is more a stylistic issue if you use it or not. Sometimes it makes the sentences easier to parse (read).

Answer 2

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.