When I was in the first grade, I left Santa a letter detailing how much I really really wanted to be a Power Ranger above all else, even if it meant that I didn't get any presents. I left it by the tree with some sugar cookies (we didn't have any chocolate chips) and a half of a Snapple that I had drank most of because I didn't want to get the milk.
The next morning when I woke up I saw that the cookies and Snapple were gone and Santa had left me a response apologizing that he couldn't make me a Power Ranger. I was heartbroken.
That was my worst Christmas, probably. Best? A few years back when I got mad gear. I don't know why, but there was this huge influx of video games under the Christmas tree and I about died. It's materialistic, but man those were good games.