Tonight with your 5 to 8 year old
The prompt
“Why do you think sharing is sometimes really hard, even when you know it's the nice thing to do?”
What to listen for
If they can explain the hard feeling ('I just don't want to'), that's honest and healthy, they're learning that doing right doesn't always feel easy. Praise the honesty, not just the eventual sharing.
If they insist sharing is always easy, that might be the answer they think you want to hear rather than the true one. You can gently say it's okay to admit it's hard sometimes.
A blank stare just means the question is abstract, ask about a specific toy instead.
What this tells you
This shows you how they're working out the difference between what feels good and what is good, which is a big part of growing character.