Regret or Hope: How Do You Live Your Life?

Alright, now this is not going to be one of those long drawn out blog posts. In fact, it's just a simple question. But I would love to have everyones feedback on it.

I have seen people who have dreams and aspirations and yet they are never realized. Life marches and on and suddenly they find themselves at the end, never doing what they thought they wanted to do. But, the amazing thing is, they never lose that zest for life. They never let the regrets of not doing what they most desire take center stage. They don't cling to what could have been, they focus on the here and now. If you were to look into there eyes, you would see a spark that cannot be dimmed.

So, my question to you is, how do they do this? How is one able to live years and even decades with unfulfilled dreams and expectations, and yet never fall into the rut of self pity and regret? How does one take each day as if it was their last? To quote a country song how does one "Live like you were dying"?

I look forward to your responses.