When listing things such as names, places, or dates...it's pretty important for the literary-astute to have the oxford comma present, depending on what ideas one may want to convey. After all, the very soul of the sentence can be altered severely with or without it.
Take this sentence (and its variation) for example:
To my parents, Ayn Rand and God.
To my parents, Ayn Rand, and God.
There are many ways to interpret the first sentence. It's ambiguous whether "God" and "Ayn Rand" are your parents in the first. In the second, all ambiguity is erased - it's clear that your parents are two totally separate people from "Ayn Rand" and "God". )
As a child in Canada, I used it initially. Then around Grade 4 or 5 in Beijing (at an American school...) they told me not to use it. After moving to my current (British) school, I was taught to use it again (my English teachers for the past 4 years have been either British or from Commonwealth countries). So now I use proper punctuation again. Thanks, Great Britain!
I find this interesting as in my English class last semester I noticed that some students were previously taught to not use the Oxford comma, while others (myself included) were. I use the Oxford comma as I think it is the proper way to list things. It also lessens possible confusion within a sentence as Ventus showed through those examples.
Another example of how the sentence can dramatically change:
- Toast, juice, macaroni and cheese.
- Toast, juice, macaroni, and cheese.
Clearly the serial comma would not work here. But I wonder, in a society that does not use serial commas, and thus write all their sentences without them, Mac and cheese would appear without the comma, no different than trucks and pudding. So how (lets assume that people didn't know Mac and cheese go together) would people know a person is saying Mac and cheese as a single entity?