Well, it could be that Robin did something seriously wrong that warranted such a reaction from Batman. Maybe it was a moment of misunderstanding or a test of Robin's character. Another possibility is that it was all a setup for a greater story arc.
It could be a moment of misunderstanding or a test of Robin's resolve.
It could be for adding drama or showing a conflict between characters. Maybe one character got really angry and lashed out.
The reason for Batman slapping in a comic can vary. It could be to defend himself or someone else, or it might be a symbolic act to demonstrate his authority or moral stance in a particular situation.
Maybe she was really angry or felt provoked in that moment.
Maybe she was really angry and felt the need to express her emotions through a slap.
Maybe Sally was really angry or something happened that made her react that way.
Well, there could be many reasons. Maybe there was a disagreement between Robin and Batman on how to handle things, or Robin felt it was time to develop his own identity and methods away from Batman's shadow.
I have no idea. Maybe it's just some strange fictional idea someone came up with.
Sometimes in comics, such actions are used to create drama and tension. Maybe it's a setup for a bigger story arc where they have to overcome this conflict and grow stronger together. So, Batman hitting Robin could be a catalyst for future developments.
In some fanfiction, there could be an emotional outburst. Batman has a lot of pent - up emotions, and if Nightwing accidentally triggers him by saying something about his past, like his parents' death or his own failures, Batman might lash out and slap him. It's a way to show the complex and often damaged psyches of these characters in the fan - created stories.