Mark Watney is left behind on Mars when his co-astronauts have to leave the planet because a Mars storm is brewing. He got separated from his group when a gust of wind gusted him away and he got injured. He was presumed dead and they left.

He was left with the supplies in their little space dome, Mars Rover and some other stuff. There was no way to communicate with anyone and the next mission to Mars was only due to arrive four years later.
So now, with only so much food for their mission, no way of communicating with anyone and all alone, what do you do?

And this here message is why we love this movie: work the problem. Never ever give up. Always stay hoping.

What to do when you don’t know what to do? Break the problem up in pieces and work each piece. Apply your mind. No food? Use your fellow astronaut’s shit to grow potatoes from the potatoes that were supposed to be used for Thanksgiving. Need to communicate with earth? No problem, use a discarded Mars Rover’s communication device. You had problems before and you solved them, why should being deserted on another planet be any different?

Wanna give up? You’re gonna die if you do. You cannot afford to give up. On anything. Whether it is to stay alive on Mars or to find a career you love.

Work the problem. You had problems before, you solved them, solve this one.

And always hope. Because hope is the fuel for everything.