Yet he was happy.
I know him not at all, but in that moment that man was the definition of creating your own happiness. He had prayed the Serenity Prayer ("God grant me the serenity to accept the things I cannot change, courage to change the things I can and wisdom to know the difference") and accepted his physical limtations. But he refused to accept that he is a victim. He took responsibility for what he could control and, in doing so, created his own happiness. Just what he could create, and just in that moment.
I am grateful for that which I do have and humbled by his existence. He is powerful, indeed.
Feel free to leave your own reminders to take stock and give thanks in the comments.