It's good to avoid hurting someone's feelings.
Nancy walks into the house where her children are cleaning up as a surprise for her.
Nancy wants to react to the children's efforts.
Nancy tells the children what a great job they did and overlooks all the imperfections.
Nancy points out all the things the children could have done better.
The children feel great about themselves and learn how to do a better job as they grow older.
The children feel like they're not good at cleaning and don't try again.