He could become more isolated. After being punched, his friends might avoid him for a while. For example, if Harry punches him, Harry might need some time to cool off and not want to be around Ron. This would make Ron feel really lonely and regret his actions that led to the betrayal.
It could be Draco Malfoy. In some fanfictions, Draco might be pushed to such an extreme by his family's beliefs that he resorts to physical violence against Hermione. He might punch her out of jealousy or to assert his so - called superiority.
Maybe it's a story where Hermione accidentally gets caught in the middle of a wizard duel gone wrong. One of the angry duelists punches her in a fit of rage. Then the story could focus on how she deals with the injury and the chaos that follows, as well as her pursuit of justice for the unprovoked attack.
Well, it could be Harry who punches Ron. Maybe Ron betrays Harry's trust in some way, like perhaps revealing a secret of Harry's to the wrong people. And Harry, being really angry about it, punches him in a moment of rage.
Well, in a 'peter gets punched by steve fanfiction', it could be that there is some sort of misunderstanding. Steve might think Peter has done something wrong, like endanger the safety of others or break a moral code in their world. Or perhaps it's part of a bigger plot where an outside force is manipulating Steve into attacking Peter.
One possible plotline could be that Clint is on a mission. He gets ambushed by a group of enemies. First, he's punched during the initial struggle. Then, as he tries to fight back, one of the enemies stabs him with a knife. Just when he thinks he might escape, he gets shot by a sniper. His fellow teammates then have to race against time to save him.
Clint would probably be in a lot of pain, but his training would kick in. He might first try to assess the severity of his injuries. If the punch didn't daze him too much, he'd immediately start looking for a way to counter - attack those who are attacking him. Even if he's been stabbed and shot, he'd use his skills to find cover and plan his next move.
One reason could be a difference in ideology. Steve might have very traditional views and Peter's more modern or reckless approach could clash with that, leading to Steve's outburst.
Given only 'dateline karen read story', Karen's identity remains a mystery. She might be a staff member at Dateline who was reading a story for work purposes. Or she could be a person who was interviewed by Dateline and was reading a story during the interview, or she could be an ordinary person whose story - reading experience is being highlighted in relation to Dateline.