The next time your hope or ambition is thwarted, and you believe that you didn't get what you wanted, think about the quote above. The problem so many of us have is that we're not happy with what we've already got. We believe that there is something or someone else out there, outside of ourselves, that will make us happier than we are now.
It's really so much easier to simply find a way to appreciate what we've got. That's not to say that we should all become complacent. Doing things to make other people happy is a wonderful diversion from trying to do so for ourselves. Just remember that you are the one who is ultimately responsible for your happiness, not the "something or someone" that is outside of you.
While trying to make others happy, also remember that they are ultimately responsible for their happiness as well. Don't blame yourself if you don't think you did enough to cheer up a friend, or you weren't able to give them that gift they really wanted. The greatest gift you can give is to help someone realize that they already have everything they really need. Sometimes this is the gift you need to give yourself.
Sit down today and try counting your blessings - list things like family, friends, pets, mobility, a satisfying job, shelter, financial independence, food in the fridge - any and all things great and small. Stand back and take a look at the "Big Picture." No matter what you think you want, you'll realize that you've got it pretty darn good right here, right now. Anything else is just icing on the cake! Enjoy the sweetness!