Is my iPhone basically indestructible?

I have a white iPhone 4 and I got it like 2 weeks ago and I wanted to be an idiot and crack the back of it so I could color it with sharpies and whatnot, I've dropped it hard on tiled floor, concrete and a brick wall pretty high up and nothing happen even though it sounds like it did some damage, I probably sound stupid, I've even slammed it on the floor and on a wooden dresser and still hasn't cracked and the phone is still flawless

You're stupidity hurts. I think I got cancer reading this post