I assume its when you attempt to make the far fetched idea of a superhero really really serious. When in fact its a crazy notion ...you attract people who are crazy and want to be taken seriously.
Not that I didn't like the Batman movies, but what I absolutely loved about The Avengers and especially Captain America was its getting away from being so dark and gritty, Acknowledging itself as based off a comic book ..acknowledging its premise as out of this world ..not in it, and bringing us there.
WhazZo
I'll shut up.