What is the Oxford Comma?

It's a hot and heavy controversy in the grammar world! Basically, an Oxford comma is a type of serial comma - which is a comma that separates things in a list. The Oxford comma comes specifically before the coordinating conjunction (a fancy word for 'and, 'or', and so on) of the penultimate (before last) item in a list that has three or more items. HOWEVER the debate is - should we put a comma there at all?

This is an example with the Oxford comma- I need to buy juice, bread, and honey.

This is an example without the Oxford comma- I need to buy juice, bread and honey.

This is an example which doesn't fit the debate because it doesn't have enough items- I need to buy juice and honey.

What do you think? I personally use the Oxford comma, because it makes the sentence neater, clearer, and cleaner (see what I did there?)