Why do people climb mountains?
Why do people do bungee jumping?
Why do people watch tv?

We don't need a man on Mars, we need plenty of people there. Going to and living on Mars is the next logical step in the evolution of mankind. Not again a "go there and quickly come back"-stunt as Apollo. Having a self-sustained permanent colony on Mars is the only sure way that mankind could survive a catastrophic event on Earth, either naturally (impact), technology gone wrong or the big mushroom blossoming.

Harald