Thinking about Kirby's writing reminded me of a piece of writing advice he gave that's stuck with me ever since I read it. I've reinterpreted it and probably misquoted it through the years, so I want to document it here in case I need to refer to it again.
In an interview posted at the Jack Kirby Museum, Kirby said that "Superheroes may be superhuman in stature but inside they’re human beings and they act and react as human beings [...] It doesn’t matter whether you’re doing legendary characters like Hercules or modern characters, you’ll find that humans are humans and they’ll react the same way in certain situations."
That's profound and like I said, it's always stuck with me. You can put characters into all kinds of crazy, outlandish situations, but as long as they act like real people, as a writer you'll always be okay.