[jakubw]

You don't need to look too far for examples. Even on this very site, there are quite a few people who want to make a huge difference with their lives in one way or another before they're 30 or 40. Because they know they probably won't have another shot at it later on. What would that number be if they had an infinite number? Many wouldn't probably ever get around to try.

[polyfractal]

How many people try to make a difference in the world, fail (because it is hard) and then capitulate into working a salaried job managing database queries for MegaCorp...because it is safe and they have a family to feed.

If you knew you would live until 300 and remained reasonably "young/healthy" during that time you probably wouldn't start a family as soon.

[kiba]

I don't think a 20 years old doing startup is thinking "I gottach do this before I die!". No, it's just...let do it man!

[kls]

Right at the higher levels of human achievement, I believe that it is curiosity and inquisition that drive us. Certainly impending death can focus people, but I do not believe it delivers the spark that lights ingenuity.

[joelrunyon]

“Remembering that I’ll be dead soon is the most important tool I’ve ever encountered to help me make the big choices in life,” - Steve Jobs

A few months ago, this was one of the biggest quotes around the internet. For a lot of people, death is a catalyst to do something that matters. In the biography, Jobs talks a lot about how he's in a hurry because he feels like he's going to die young.