I think making a heroic character, even a superhuman one, be human is something that's not easily achieved by most people. You have to make them have realistic flaws as well as strengths. I hate to resort to this example, but the best one I can think of right now is Batman. We all know about Batman as that kind of non-superhero superhero that can do extraordinary things, even beyond the scope what his limits should be.
Where Batman shows a side that's not really consistent with what we know him to be. As with most superheroes, they put all on the line to save people - but what happens when you cannot save someone? What happens when there is no happy ending at the end of it all? Heroes should always be allowed to fail, but the importance is in the context of how that failure is brought about. Failure for failure's sake is nothing more than poor writing and lack of an imagination.
Where Batman shows a side that's not really consistent with what we know him to be. As with most superheroes, they put all on the line to save people - but what happens when you cannot save someone? What happens when there is no happy ending at the end of it all? Heroes should always be allowed to fail, but the importance is in the context of how that failure is brought about. Failure for failure's sake is nothing more than poor writing and lack of an imagination.