I'm amazed by the human body and could probably make lists and lists of the things that amaze me about it. I'll narrow it to the top three though:
1. Conception actually being possible
The players involved in this process are TINY. After every hormone comes together and perfectly synchronizes, these itty bitty half cells are actually capable of not only finding each other, but knowing exactly what to do. Sperm! It's amazing! (Forgive me if my enthusiasm is coming across inappropriately!)
2. The ability of a breast to actually produce food
No, really, boobs. They certainly don't look like things with tangible superpowers, and yet, food! Such a complex ability!
3. The heart - it's just amazing in his complex it is and I'm blown away by it
First you have mechanical stuff. Then you also have chemical stuff. Electricity, too?! And if you look at the electricity, you can see if something is wrong. (Well, usually.) Some people aren't cardiology people, and I can see why. It goes beyond thinking 3-dimensionally. I'm a firm believer in evolution and it gets me so dorkishly giddy to imagine all that had to happen to create something as beautiful as the heart. Sure it has its weaknesses, but it's amazing!
So what about the body amazes you? (Feel free to be silly if fits the question. :) )