Grammatical obsession

Rico says he's constantly correcting spelling and grammar in the stuff he posts on his Rant, but it's the non-use of serial commas that makes him cranky...
(For those unfamiliar with the problem, Rico will reuse the example (a book dedication) given by his buddy Rani, when we both worked for Apple:

"The author wishes to thank her parents, Ayn Rand and God."

One little missing comma, a very different meaning...