Wash your hands

Luke came out of the bathroom yesterday and said "I'm sorry mom but when I wash my hands I have to wash under my fingernails, between my fingers and EVEN my wrists." He said this with a lot of conviction and I asked him if he learned that at school. Yep. They taught my kid the proper way to wash his hands. I'm still not sure why he is sorry about it though. I'm just grateful for school so I don't have to be the one hounding him about everything.