Teenage rebellion for the Winchesters started when Dean came home with an earring in his left ear.
John thought Dean was going to be the easy one, and with the way Sam was marveling over his older brother's new accessory, John was sure his youngest now had new ideas to piss off his father.
John ignored it.
That's what the parenting books all said to do. They said that kids needed to feel like they were in control of their own decisions, so John would pretend to be okay with Dean having that thing in his ear.
The week after that, Dean came home with a ring in his ear, and John wasn't sure where the kid was coming up with the money to fund these new accessories of rebellion. John only breathed deep and pretended this wasn't happening.
When Dean came home with blue hair and a stud in his chin, John lost it.
"I'm not going to have my son look like a punk wannabe," John had said after the initial lecture was over. He was sure Sam wouldn't repeat what Dean had done in the future.
Late in the night, while John was researching a hunt and had sent the boys to bed, Sam looked over to Dean's side of the room they were sharing and asked, "Are you mad that dad yelled at you?"
"Nope," Dean answered. "I'm just glad he didn't know about the tattoo on my ass."