I'm stranded on Mars.
I have no way to communicate with Earth.
I'm in a Habitat designed to last 31 days.
If
the Oxygenator breaks down, I'll suffocate. If the Water Reclaimer
breaks down, I'll die of thirst. If the Hab breaches, I'll just kind of
explode. If none of those things happen, I'll eventually run out of food
and starve to death.
So yeah. I'm screwed.