Sometimes there is a good reason to use the Oxford comma, especially if you need to separate the last two items on the list. Here's a good example, taken from a question that was asked a short while ago, with thanks to the OP and to Phil who corrected the sentence:
"my mother's best home cooking — broiled fish, fried cabbage, and lobster."
The corrector chose to add the comma after cabbage to indicate that these were three separate dishes. Without the comma, we would understand 'fried cabbage and lobster' to be a single dish.
Another classic example is this:
"I'd like to thank my parents, Arnold Schwarzenegger and Mother Teresa of Calcutta."
"I'd like to thank my parents, Arnold Schwarzenegger, and Mother Teresa of Calcutta."
Unlikely, but it's one you'd remember!