My parents' loud fights made me terrified of any disagreement
I think kids who hear parents argue too much grow up avoiding conflict. It took me years to realize that healthy debates exist. This fear shaped my own relationships badly.
Developed a habit of jumping to apologize for literally anything just to stop tension before it starts. Once apologized to my roommate for the weather being bad during her picnic, which is both pathetic and makes zero sense. Guess I went from conflict-phobic to conflict-preemptively-sorry, which isn't much better.