Robots are meant to provide scientific data about Mars ecosystem, explore further on the surface and so on. What does a men, right now, add there? Nothing. Just danger and wasting money.

Now, investigating technology that could put a man on Mars, that's interesting. But not just for setting foot on the surface, just for bringing to reality new tech that allows that.

Curiosity is an achievement itself. Great technology, and for now, greatly executed. How many different proves went to the moon before a man could set its foot on there?

It's not embarassing that in 40 years "we" haven't gotten anywhere else. To me it's embarassing that in 40 years we do not have yet sustainable way of keeping life on our own planet. Energy, on Earth and beyond, it's what could set a new standard for human race.