When you watch your father die a painful death from Colon Cancer, you come to realise what is and what isn't important in life. Try to live your life with no regrets and never take anything for granted. Most of all do the things that make you happy.
My personal view is we are here on this Earth to make a difference in the lives of others. If the people in your life (family, friends and those you come in contact with) are better for knowing you, then you've done your job.
This quote from Morrie Schwartz sums things up nicely
"So many people walk around with a meaningless life. They seem half-asleep, even when they're busy doing things they think are important. This is because they're chasing the wrong things. The way you get meaning into your life is to devote yourself to loving others, devote yourself to your community around you, and devote yourself to creating something that gives you purpose and meaning."
— Mitch Albom, Tuesdays with Morrie