Why birthday parties are a good indication of eternity

So, nothing much of great excitement or import has occurred recently, but last night, I had an invigorating chat with a good friend. One of the topics that I had expressed had been concerning me of late, is how our appetite for real transformation and eternity is so small, that our imagination for the eternal is so limited, that we do not desire it, and we do not long and crave for it.
Small children, in anticipation of their birthdays, are whipped into such a frenzy that EVERYTHING revolves around the birthday party: how many of their friends will come, what lovely presents are going to arrive, how amazing the cake and ice cream is going to be, how much FUN they're going to have. Children can be excited for weeks in anticipation of its arrival (having small attention spans, however, I suppose it's hard for them to be excited more than a few weeks in advance), savouring and anticipating every moment on that day. Some will act "extra good" in order to make sure that the day will be all that they hope it will be. Some will invite every kid that they know on the planet, in order to maximize the gifts and the ice cream available. Some can't sleep in the dizzying excitement of what will happen!
And, folks, this is for a child's birthday party. I often wonder why we cannot muster the same kind of enthusiasm for an even greater celebration. Why our visions and dreams are so limited (to our own nation, our own kind, our own people), that we cannot see larger, cannot see all the 'kids in the neighbourhood' who also are coming to the party. Why we are not so dizzy with anticipation that all we strive for, all we seek for, is that eternal celebration. Why we kind of don't really want everybody to come to the party either.... I can't figure out why we think this way...