This is not a new idea but I'll go first 
Best- Christmas when I was a kid, nothing beats waking up and running down the stairs to see what Santa had bought us. None of the stress and all of the chocolate!
Worst- ex-MIL came over, was rude about the house, gave some awful presents, demanded a three course meal be done in 45 minutes so she could go back home to get back to the dog. It was perplexing as she was usually lovely but seemed to have left her manners behind that day!