"The world embarrasses me, and I cannot dream that this watch exists and has no watchmaker."
-Voltaire
Christianity loves that quote. The watchmaker analogy just seems so perfect, right? The watch didn't just naturally happen of course.
But why did the watch not just naturally happen?
Well, let's look at a watch.

This is obviously a creation of humans. Because we can see that it has a band to wrap around our wrist, a perfect circular display with lines to represent time and hands to point to those lines. It's too precise to be a natural occurance, and we can instantly realize what it was made for... to tell time.
But can you really describe the world as a watch? Let's look at some pictures of nature.


Wait a minute, that's a bit different isn't it? There aren't any straight lines or perfect shapes, there's nothing in nature that is built for a single purpose. It's random, it's everywhere, we may have more than we need of it, maybe less.
Not to mention, we already know how plants come about -- they grow from seeds in the ground. I wonder, if pollen had human intelligence, would it theorize that the flower -- a natural occurence -- is evidence of a God?
Anyway, it is true that the earth serves the purpose of giving humans a home. But think about it, if all human creations just suddenly disappeared, how many people do you think would end up dead? A few million? A few billion? It's very nice and easy to call the earth the perfect habitat for a human when humans of the past have made survival such an easy thing for us. Surviving without human creations on the earth, is a very difficult thing indeed though.
What I'm getting at, is that nature is completely random. When a tree is planted, it could sprout up and be leaning toward any direction. In a million years there could be a mountain where I am sitting, or there could be a sea. I think the observable process of change in nature gives us a small glimpse into how it works, and possibly how our world was actually formed. Far from being comparable to a watch, if you ask me.