Thankfulness

Why are we as humans so slow to be truly thankful for all we have? We are promised nothing and spoiled rotton, yet we never have enough. We always want the next best thing. Our kids have to be better off than we were. Were we really that bad off? I wasn't. I had (and still have, thank God) awesome parents. I could not ask for a better wife. My kids are amazing. My son Kody is an amazing kid. The older he gets, the more I see it. He makes me laugh, but he never has enough. He always wants more, or the next best thing. That frustrates me because, although everyone wants things, he is never happy for what he has, at least not for long. Aren't we all that way to an extent? Why is that? What is missing in our lives that makes us always want to fill that void? God.