As I student, I never misbehaved. I was in an environment where everyone else was mostly doing what they should be doing, so I guess I just got in the habit of doing what my teachers asked me to do. Since this kept working out very well for me, it never even occurred to me that I could or should disrupt class, be mean to the teacher or other students, throw things, etc.
I really don’t understand misbehavior. Sure, on an intellectual level I am willing to accept that a student might misbehave because they don’t understand the content and therefore are either bored and trying to entertain themselves or they are trying to cover the fact that they are lost. Or, if a lesson is going too slowly and a student gets bored, or if a student is upset about a family issues or a social issue, or an issue in another class, or any number of other things which could lead a student to not be doing what (s)he should be doing.
However, what mystifies me is the step that connects one of those causes with the actual decision to talk over another student who is asking a question, or throw a ball of paper at the back of the teacher’s head, or take a piece of paper, tear it up into little bits and throw it all in the air, etc. What goes on in the head of a student who is confused and then thinks to himself: “Ok, I am confused. Therefore, I will toss a ball of paper at the teacher.” I really have no idea how that thought happens.
There is an episode of The West Wing in which CJ, the press secretary, admits to someone that she doesn’t remember exactly what had happened on the night of a shooting that she was present for, and that all of the information she had been sharing with the press was based only on what other people had remembered.
I feel a similar way with regard to my understanding of discipline issues. I can recite an explanation of why people might misbehave and some ways to prevent those things, but this is all based on other people’s understanding of this topic. I really don’t understand why people misbehave, I am just basing my understanding and my (attempted) solutions on what other people have tried to explain to me. I do not understand what is going on in the head of someone who is misbehaving, and this makes it hard for me to prevent that from happening or stopping it once it had started.
I wonder if there is a special class on classroom management that could be taught to people who were the “good kid” in school that would help us actually understand misbehavior. I would take that class.

Sadly, I don’t think any “special class” could ever teach the classroom management skills that just come with years of teaching experience. But maybe the closest thing to what you’re referring to would be an educational psych or child psych class. Or maybe just imagine being in the kids’ shoes…imagine being in the most mundane AND difficult class you could be in. For example, maybe an upper-level class in a foreign language that you don’t understand. Imagine you had to sit there for 90 minutes and pretend to understand (and care) what was going on. Chances are, as a college student, you’d dick around on your computer or phone, or maybe you’d even leave the classroom (or skip class) because college students have those options. But middle schoolers certainly don’t, and when you dab the bit of immaturity they all have, plus maybe a lack of appropriate mannars that some are never taught at home, it really makes sense why they act the way they do.