I'm thankful for my life as it is. Out of all the possibilities, sure, there are a hundred scenarios in which I'd have a better job, stable family by now, or something like that. Of course, I could also have ended up dead in a ditch at 16 if that car had hit me a hundredth of a second earlier. So on the balance, I have a pretty good life.
I do wish that I had an animal, but with my forgetfulness, it'd be a pile of bones by the time I remembered to water it. This is why I don't have kids, and why my plants are perpetually brown.
I'm thankful for my friends in Japan, the US and around the world who hang out with me, put up with my crap, and let me sleep on their couch. I'm thankful for being able to enjoy my life to the fullest. That's what matters.