Carla H. Krueger said this quote

For no real reason – well, perhaps because of the seriousness under the trees or Nader’s hair, which was very messy and covered in little grass seeds – Katie began to giggle. She knew it was wrong, yet it was also natural. She covered her mouth with both hands, but Nader was already pale with revulsion. He turned and marched away into unwanted sunlight, leaving her to wonder why bad things happened and why no good person prevented them.