Two of the greatest words my parents ever taught me while growing up were "thank" and "you." At the time, it seemed like a polite thing to say when someone else did something nice for you. As I grow older, the significance of these words becomes more understood.
Gratitude can be thought of as a multiplier of good things in life. By the law of attraction (also known as the law of love) what we give we shall receive. Gratitude is also a form of love, and by giving thanks we are giving love. This is a really great way to bring more positive people, circumstances and events into our lives. The cool thing about this is that you can feel and think this way any time you choose! If it's hard to find something you're grateful for, you can always fall back on the things we might take for granted (running water, health, eyes, ears, friends, pets, nature, etc.) By really dwelling on the things we appreciate and love, we can turn around a tough day or create better days for the future. :)
In closing, a certain inspirational figure comes to mind on this subject. Is it any coincidence (if you believe in coincidences) that one of the greatest minds that ever lived, Albert Einstein gave thanks at least a hundred times a day? Could it be that life revealed so many of it's mysteries to him because of his understanding and practice of gratitude on a daily basis?
"A hundred times every day I remind myself that my inner and outer life depend on the labors of other men, living and dead, and that I must exert myself in order to give in the same measure as I have received and am still receiving."
- Albert Einstein