In order to make your writing clear, you need to use commas ... This sentence has a subordinate clause: 'When Albert saw the food'. Subordinate clauses do not make sense on their own because ...

If you include a comma before the "and" and final item, you are using the Oxford comma. If you leave out that final comma, you do not abide ... last conjunction of a sentence.

depending on the list you are writing out, omitting it can lead to some confusion. A Reddit user found what could be the best three sentence arguments in existence for the use of the Oxford comma ...