Resentment is a stupid word for unexpressed feelings.
This I reckon because my kids have none. And all their feelings pour out of them. Mostly I watch it happen in amusement.
I wonder if as kids get older their social conditioning starts to cause suppression.
It’s not good manners or socially acceptable (or cool) to let it all hang out emotionally.
So what we perceive as attitude is actually the burgeoning resentment.
Gotta get it out with some roaring.