In first grade, in music class we were playing hangman for some reason, and when it was my turn I thought it'd be funny to say "fart". Kids laughed of course, but the music teacher got in my face and he said slowly to never say that word again, and then my teacher pulled me aside before recess to give me a scolding about saying inappropriate words.
In 8th grade English class, we had a lesson on the difference between "who" and "whom." When asked to give examples of each being used properly, the popular athlete in our class offered, "Who farted?" as an example. At least half the class expected him to receive after-school detention for using a bad word. Surprisingly, our teacher despite her initial shock and our gasps and laughter didn't react negatively and continued the lesson as if it was no big deal.
Some of these may be repeats from my Share Your School Stories posts, but I'll keep them brief and on-topic.
I also discovered that some teachers really hated it if you were just sitting quietly and drawing in class. I could be done with classwork and not have anything else to do, so I would just pass the time doodling in a sketchbook or on a piece of paper. It didn't matter what I was drawing, they claimed I was distracting/disrupting the class by doing it. I don't know if they hated art or just wanted their students doing assignments all day.
In 8th grade, a substitute yelled at me for having my head down on my desk once I finished the current class' assignment and all the other homework I had up to that point. She refused to believe I had all my work for the morning done already.
Little-Me would get so worked up about it I'd be practically sobbing cause when you're 7, getting in trouble is like getting convicted of war crimes.
I ended up crying like this in 5th grade when I was told a classmate accused me of calling her a bitch even though I never heard of the word until that moment. After denying the accusation, I was told, "She doesn't lie," and my only choices were to confess or be sent to the principal who would suspend me. Given the principal's negative reputation, I figured confessing to something I didn't do was the lesser evil even though I hated the fact both our teacher and the guidance counselor bullied me into it and refused to even consider my side of the story. I always suspected another classmate who loved using dirty language did it and somehow managed to get away with it because he was more popular than I was at the time.
Other dumb things that led to trouble:
1st grade: My neighbor and I received pink disciplinary slips to take home because we slid on a patch of ice between the playground and the cafeteria on the way to lunch. Contrary to what was alleged, we didn't push or run into anyone. We simply glided on the ice as if we were skating. Still, both my neighbor and I got more than an earful from our parents when we came home.
2nd grade: A classmate and I chose to go back to our classroom early after lunch recess. Our teacher found us, yelled at us, and made us go back outside only to immediately call us back inside because recess had just ended by this point. We might have understood her disapproval had she told us we couldn't be in the classroom unattended, but she never brought that up in yelling at us.
7th grade: The same teacher from the 5th grade bitch incident removed me from the gifted student group with the claim I had too many missing assignments. When I asked both my regular teachers about this, however, both stated I had no missing assignments at all. Needless to say, any respect I still had for my old 5th grade teacher largely disappeared after this; I felt a teacher that would bully a student into a false confession and later lie about having missing assignments was total BS.
8th grade: After liking a short film so much I wished we could see it again, I was scolded for telling the teacher in my best Bogart voice, "Play it again, (first name)." To add insult to injury, she actually told my parents about this at parent-teacher conferences even though we had two other guys in my class who said much worse stuff on a near-daily basis and never seemed to get into any sort of serious trouble for it.
Also in 8th grade, the playground monitor with a reputation for being mean made me stay inside the school entrance because I didn't have a jacket to wear even though it was 50 out (10 Celsius). Oddly, another student without a jacket and no explanation for the lack of one was allowed to keep playing because they were a classmate of one of her kids As an aside, it was amazing that many students and parents alike were fully aware of this preferential treatment that occurred quite frequently during the school year while teachers and staff refused to believe it happened.
12th grade: After finishing an AP English research project early, a classmate and I chose to quietly play cards until we were dismissed at the end of our class period. A particularly old and nasty librarian ree'd at us for it and told our equally nasty teacher. The next day, we were told we had to write formal apologies to the librarian (I purposely misspelled her last name just to be an edgelord) and a 500-word essay on the evils of card-playing. Had she not ended up with a brain aneurysm a week or so later (and never taught again after that), I have a feeling she was set to tell our parents at the upcoming parent-teacher conferences what awful monsters we were for the horrible crime of quietly playing cards in the library to pass the time after finishing our project.
(Edits for clarity & a typo.)