And, actually, I think that there's something very interesting when you compare The Hulk and Superman.
Both characters are based on a very simple premise: The fantasy of a weak, helpless, socially ineffective person having a strong, capable, badass inner self that they can unleash upon the world and prove everyone wrong.
In Superman's case, it plays to the fantasy. Clark Kent is a working class schlub with a nine-to-five job who every now and then turns into the coolest guy on the planet who everyone loves and who nobody can push around. All in all, it's a validation of that fantasy.
The Hulk, on the other hand, is the dark reflection of that. Bruce Banner, like so many weak willed, put upon weirdos, longs deep down to be strong, to be able to stand up, and to turn the tables on everyone who ever pushed him around. When he got his powers, he got his wish exactly. And it was the most horrible thing that ever happened to him or the people around him. The Hulk explores the notion that those power fantasies are deeply destructive. They come from a place of anger and when we indulge them we can hurt ourselves and others.
What's more interesting, both characters, as they've developed, have explored the notion that the solution is to find a balance between the fantasy and the reality. For The Hulk, it's obvious. When he's out of control, he's dangerous. He hurts people, sometimes innocent people. Wether not he's the hero or the villain of the story depends entirely on who he's mad at at any given moment. But when he's in control, then he's at his best. He has the intelligence and compassion of Bruce Banner, as well as the strength, courage, and endless willpower of The Hulk. When he accepts the driving motivations of his power fantasy, his anger, without losing himself in it, then he can use that to change himself into a better man.
That's all pretty obvious for The Hulk, but it's also very true for Superman. We've seen, time and time again, that while Superman is Clark Kent's fantasy, Clark Kent is also Superman's fantasy. He needs to ground himself with Clark Kent's daily normal life or he will lose his humanity. Superman is wonderful. He's strong and courageous and always says and does the right thing and everyone loves him. But he's set apart from people. He stands above ordinary humans, unable to enjoy the simple pleasures of life, unable to connect to people because he is inherently other. There is something very cold and very lonely about Superman when Superman is all that there is. That's why Clark is necessary. Clark can go to a bar. Clark can go to a movie with friends. Clark can act foolishly. Clark can work a nine to five job doing something he loves. Clark can be a person and live with people in the world. The fantasy of Superman allows Clark Kent to rise above mediocrity and be extraordinary. But he still needs to embrace the grounded reality of Clark, because getting lost in a fantasy of being better than everyone means that you're separate from everyone. And that's not good for anyone.
Thematically, the characters parallel in a very interesting way. A way that brings up some very interesting notions about what people want and how they navigate their day-to-day lives.