What's a birthday?

The other night we were having dinner around the table and some how got to talking about birthdays. Luke began saying, "birthday" over and over again. This got me to thinking. I wonder what Luke's concept of a birthday is. Then I glance at Nathaniel and wonder the same thing. So I ask Nathaniel, "Nathaniel, what is a birthday?" (meanwhile glancing at Cari and Noah telling them not to answer) Nathaniel is clearly coming up with his best answer. He spits out a few silly remarks and after I ask the question once again, he answers, "Well a birthday is when you've been wanting and wanting toys for so long and you finally get them. You can tell people what you want and they will go to the store and buy it for you." Rob and I looked at one another and of course died of laughter, but were quickly brought back to earth when Nathaniel shouted, "I'm not being funny!" He obviously has no concept of how ridiculously cute he is!