If you'd like any insight into these characters, here's my take: I think the Fantastic Four was really the start of a break into more realistic characters in comics.

In the Golden Age, heroes, even monstrous ones, loved every aspect of their role. The Thing was a guy who gladly took the role as a hero but hated being a monster. He would have done anything to be rid of his monstrous self while at the same time accepting that role.

Never before would a character have come into comics who made that kind of impact into the otherwise happy, perfect genre of heroism.

-Scott Redding