Loved the book!

Will see the movie, but fear I will be disappointed.

I think the key survival message in the book is that the principle of STOP (Sit, Think, Observe, Plan) was as necessary and critical part of the Astronaut's survival on Mars as it is on Earth.

There was something he could have and probably should have done, that he did not do, and that would work on Mars as well as Earth. I thought it was a fairly obvious thing to do a day or two or so after he realized he was trapped. . .

SPOILER ALERT

There was wreckage from the decent vehicle and other stuff around: he could have made a large "SOS" with it and/or rocks etc. that could have been seen by one or more of the satellites in orbit over Mars(or by a plane if on Earth). There were several satellites in orbit and they played a big part in the story later on. Instead, it was a lucky accident how NASA found out he was still alive. . . . As it turned out, no one was actually looking, but he could not have known that. This was the only thing I saw that he missed.