"Well ducks breathe air," I said, "they're not mammals."
"Yes they are," he said.
"What?!" And then we got into this huge debate about whether ducks are mammals. He said they were, because they breathe air like us, I said they weren't. He got his friends on his side... "Tell her she's stupid, ducks are mammals!" and they did, and eventually I'm sure I cried, because they were wrong and I just knew it.
I just could never let stuff go as a kid, couldn't ever brush comments off. Mom said when boys picked on me, it's because they liked me, but I knew it wasn't true because I was a total dork. I was the girl with too many freckles, and my friends consisted of the girl with bifocals, the always sick heart-surgery patient, and the fat kid. When other kids tortured me I knew it was not some secret crush. In fact usually it was girls, they were usually much more honest about calling me ugly. Boys did little mean things that I didn't understand, like ganging up on me until I'd admit that a duck was a mammal. Girls always just made sure they were understood.
Honestly, if I could write a letter to my second-grade self, it would just say, "Your life will get better as soon as you learn how to say, 'fuck off'."