[nostromo]

I think the inverse might actually be true -- that it's harder to sit in a capsule on Earth for many months compared to a mission to Mars.

In the latter scenario you're a hero on a mission to extend the reach of humanity into space -- in the former you're just some dude in a petri dish.

[beefman]

Not only that, I reckon I would tend to fantasize about leaving every time I got upset, whereas without that choice I might give up such feelings faster.