Tonight with your 13 to 17 year old
The prompt
“Was there ever a time holding onto a grudge cost you more than just letting it go would have?”
What to listen for
If they can name a moment, that's real self-awareness, they're learning that carrying anger has a price, and that lesson usually sticks better when it's their own realization rather than your advice. Let them tell it their way without adding a moral at the end.
If they say no, or that grudges have felt worth it, don't argue, that might just mean they haven't hit that particular lesson yet, or that a specific grudge still feels justified to them right now.
If they go quiet, this topic might be brushing up against something still raw, don't press, just let them know you're not trying to relitigate anything specific.
What this tells you
How they talk about this shows you how they're learning to handle their own anger, and whether they feel safe enough with you to admit when holding on didn't help.