Now to the main topic, namely, that I am irrationally concerned that after the apocalypse, I will be a drain on society. I'm not sure why, but at some point I decided that one good metric of societal worth is what I'd be able to contribute to a post-apocalyptic community. The idea came up again recently when I read about world colonization in Time Enough for Love, and one incidental character complained that although he was no good at farming, when the world developed well enough to need secondary education, he'd be the best creative writing professor ever. If you want to read an entertaining 'apocalypse' story, try World War Z: An Oral History of the Zombie Wars, which is apparently being turned into a movie.
Society would first need agricultural, medicinal, and construction knowledge--nope. I have some rudimentary woodworking skills. I might be able to point out environmental hazards at potential sites, e.g. this is a flood plain, let's move 50 feet up the hill instead. But that sort of knowledge is really straightforward if you're actually considering it, so that's not much of a contribution. I want to learn about wild edibles, which would be useful, but that'll take a while.
Once people are fed and housed, society will need to develop infrastructure for transportation to enable the development of trade so that people can specialize but still supply their basic needs. All I have on that account is an "intro to planning" class, which doesn't give me that much expertise, and people can figure out where roads and meeting places should be. Most of the planning class was saying that people had it right until they started building for automobiles rather than people, and since we won't have cars, that won't be a problem.
After the apocalypse, will we try to rebuild the world to its current state, or will we have learned from today's problems and rebuild with some consideration for the Earth and its other inhabitants? Will we be so stressed with trying to survive that we'll forget to plan and consider our long-term goals and foundations? How would you plan and manage Utopia?
Eventually society will try to redevelop technologies. I don't know anything about electronics, gears, motors, can't build anything. I know only how to utilize technologies. I know some basic chemistry and lab techniques, but wouldn't know what to combine to make what, or how to synthesize materials. I can sauter but not weld.
Yikes. Looks like it'd be cheaper to shoot me--surely people will salvage guns. I'm not the only one who would only be able to contribute my body (if not manual labor, I could be a child-bearing vessel...). What does it say about society that so many humans would be unable to survive without it?
What knowledge and skills will earn your keep after the apocalypse?