hi Darius … here is the thing: No one ever says things like that, in real life! They are contrived, humorous phrases, for all we know they were cooked up by grammar-geeks as practical jokes.
See my original reply for an example where the Oxford comma actually creates confusion.
ps: here is an example where you don’t know the # of elements ahead of time: my best friends are Sue, Molly, Jake and Saul. here is another: this episode is brought to you by the letters X, Y and Z.