The comic hero could be angry because someone betrayed him or his mission was thwarted. There could be all sorts of reasons depending on the story's plot.
Maybe he's angry because the villains are causing too much trouble.
An angry super hero comic face usually has furrowed eyebrows, a scowling mouth, and intense, narrowed eyes to show their rage.
Trust is a key theme in these novels. Because of his anger, the hero may have trust issues, both in himself and in others. The heroine has to work to earn his trust, and as she does, their relationship deepens. Another theme is passion. The anger of the hero is often intertwined with a passionate nature, and this passion spills over into the romantic relationship, making it intense and exciting.
Well, Superman might be angry in the comic because his powers weren't enough to stop a huge threat. Or perhaps there was a betrayal by someone he trusted. It could also be that the world just wasn't living up to his ideals of justice and peace.
Maybe he's facing a big threat or injustice that makes him furious.
It could be that the stakes are incredibly high and he's frustrated at not being able to solve the problem quickly. Or perhaps he's dealing with personal issues that are spilling over into his crime-fighting, making him angry in the comic.
It could be that someone criticized his work harshly, making him angry. Or perhaps he had a fight with a friend or family member.
Maybe he's angry because a villain got the better of him or something happened to a loved one.
Maybe he had a bad day at work or got into an argument with someone.
It could be because of a villain's actions or a personal setback. Maybe something happened that challenged his beliefs or goals.
Maybe he didn't get what he wanted. That could easily make him angry.