What is the have you sworn you would never do as a teenager and years later you found out you would do it?

I recently realized that I married the oh, oh, kid. You know the one in class that the teachers and students didn’t like because they always had their hand raised in class.
As a teenager I would wonder who could love such and annoying person. Funny thing is I ended up marrying one. I’ve always noticed my husband is very impatient when a game requires adding. Today he wanted someone else to add. But if they weren’t quick enough he had to tell the person how much it was and then he took over. I laughed and said he was probably the oh, oh, person in class and he smiled and knew exactly what I was talking about, because he was the ooh, ooh, person who always had his hand up.
So flutherites, what promise did you ever make to yourself as a teenager than you realize years later you broke?