The Oxford Comma: Friend or Foe?

(Or just totally gauche?)

I recently edited a driving school curriculum. I freelance write and edit, and this was a gig I took on for a friend. I was hot on the lookout for Oxford comma consistency. When I sent my editorial notes to my friend, I included a little primer on the Oxford comma, so he would understand why it mattered so much to me. (And so he could participate in these esoteric debates in the future.)

Personally, I think it's a fairly witty and helpful bit of writing, so I decided to post it here. As for my opinion on the Oxford comma, most of the time I don't use it, but I don't loathe the poor thing. :-)

Edited to add: I realized to my great embarassment that the attached Oxford comma primer contains a typo. A really obvious one.

What is the Oxford comma?

(If I had three wishes, I would use one of them to go back in time and come up with this analogy on my own. In other words, I didn't make this graphic or come up with this joke myself.)