My guess : See the world. Think about how far we've come in the last 40 years.
40 years ago, Pong was first released on home console. And now I'm using a device with orders of magnitude more computational power than all of the pong consoles ever created combined. I just asked this device where I should go for lunch. It gave me a few suggestions and helpfully drew me a map.
40 years ago, Voyager was still in the planning phases. It wouldn't be launched for another two years. And now, it's exited the heliosphere, and taken the most amazing Family Portrait ever captured.
And I can't begin to imagine how much better life is for women, minorities, homosexuals, or really anyone that's not a 'normal' white male, compared to 40 years ago
Given the option of dying at 80, or living to see what another 40 years might hold... well