I received a thank you note for a birthday party today. Not unusual, but it was from a guest to me, the hostess! Her son was invited to the party, but I invited her daughter on the spot at the drop off. Mom stuck around, lent a hand (18 8 year old boys!), and supervised her daughter and mine so I could focus on the party. Then she sent me a thank you for inviting her daughter and for throwing such a fun, creative LEGO party. It really made my day. What a thoughtful lady! It's amazing how a little note can put such a smile on your face.
PS - I did send her a thank you note for the reasons listed above. They must have crossed in the mail.