I definitely agree with you! It reminds me of a Tweet I just saw from John Maxwell, in which he said: ' "Who you are is who you attract." If you're someone who sees nothing but problems, guess what you get in life: more problems. If you see nothing but possibilities, guess what: you receive more possibilities.'
It is much better, just like you write, to be thankful for what we have, and that will make us appreciate every single moment of the day better.
Instead of complaining when my kids wake up at 5.30 in the morning, I could be thankful for the beautiful kids I have. I know several people without kids who would do anything to have someone to wake them up at 5.30 in the morning!