What’s the last thing you said to a kid that actually mattered?

I just had a student ask me why we still teach about the Civil War. Not 'why,' but 'why still.' I didn’t have a good answer. I mumbled something about memory and consequences, but it felt like I was dodging. Now I’m wondering—what’s the last thing you said to a kid that wasn’t just filler? Something that stuck in your throat afterward?