I am a big fan of the Oxford Comma (alias the Harvard Comma or Serial Comma).
What's that, you say? You don't know what the Oxford Comma even is? That is okay. I recognize that we can't all be grammar freaks, so I will tell you that the Oxford comma is the comma that is inserted before a conjunction in a list containing three or more items.
For example: I went to the park with my kids, Briar, and Hillary.
See that little comma there after the "Briar"? That comma is important. Do you see what would happen if we removed the comma from this sentence? It would become this:
I went to the park with my kids, Briar and Hillary. And -- poof! -- like that, I've suddenly gone from walking to the park with my two little boys and their two live-in aunts to walking to the park with my two grown female children. How did I get so old so fast?
Or how about this example:
I like the following kinds of pizza: Pepperoni and Cheese, Green Pepper and Olive, Anchovie and Onion, and Canadian Bacon and Pineapple.
This sentence is perfectly clear, but what happens when I remove the final comma? This happens:
I like the following kinds of pizza: Pepperoni and Cheese, Green Pepper and Olive, Anchovie and Onion and Canadian Bacon and Pineapple.
So do I like three kinds of pizza (Pepperoni/Cheese, Green Pepper/Olive, and Anchovie/Onion/Canadian Bacon/Pineapple) or do I like four kinds of pizza (Pepperoni/Cheese, Green Pepper/Olive, Anchovie/Onion, and Canadian Bacon/Pineapple)? Without the Oxford comma firmly holding down the boundaries between pizza toppings, the answer to this question is anyone's guess. And that is a travesty.
I will admit that the oxford comma is not always a necessary component of a clearly understood sentence. The following sentence, for example, is simple enough to understand:
I like to eat, drink and be merry.
However, the Oxford comma creates a more accurate visual representaiton of the way lists sound when spoken aloud: One generally says "I like to eat (pause), drink (pause), and be merry," not "I like to eat (pause), drink and be merry." That would sound foolish.
Hence, the Oxford comma should always be used. It's simple and straightforward, eliminates ambiguity, and creates a more aesthetic sentence structure. Why wouldn't everyone consistently use the Oxford comma?
The unfortunate thing is that, sadly, not everyone sees it that way. People omit the Oxford Comma all the time. In fact, the entire Associated Press has completely turned its back on the Oxford Comma. This is just plain wrong and it needs to be changed, so now that I've explained to you why this is so important, and you are fired up about the essential nature of this very special comma, I'm going to encourage you to write to your local newspaper and beg them to bring back the Oxford comma. One periodical at a time, we can bring clarity and reason back into the press.