They may experience guilt or shame.
Consider all the emotional and intellectual development happening for a third grader. It can be a stressful time. Some kids use their new ability to think deeper and their overly negative opinions against themselves in a strong, potentially damaging way. This can be hard for others to detect because third graders are better at hiding their feelings than ever before.
What you should do: Be on the lookout for the difference between temporary emotional flare-ups—anger, frustration and sadness—and a deeper sense of guilt or shame. Talk with your child about his expectations for himself, and help him find a reasonable balance. Encourage him to forgive himself. Talk about how to act in the future, not about what happened in the past.