Give pets as presents: No matter how much the grandchildren promise to be responsible for a new puppy or kitten, a new pet is a huge responsibility that should always be approved by the parents. Remember, a dog is for life . . . not just for Christmas!
Tease about romantic interests: "Is that your new girlfriend? Do you like her?" Teasing grandkids about their romantic prospects might discourage them from sharing about their love life in the future, so don't put any undue pressure on crushes or dates.
Advise Mom to work or stay at home: While becoming a stay-at-home mother used to be the norm, it's not always realistic or desirable for modern mommies. Grandparents should allow their daughter to make her own decisions about a chosen profession.
Hop grandkids up on sugar before sending them home: Pixy Stix are wonderful, but feeding 25 of them to small children is not. Don't be that grandparent.
Pass on prejudices: "It's just how I was raised" is no excuse for racism, sexism, or prejudice of any kind. Conveying these feelings to grandchildren is absolutely unacceptable under any circumstances.
Interfere with the bedtime routine: Getting the grandkids all riled up before bed might be OK when they're staying at Grandma and Grandpa's house, but disrupting the sleep schedule at their parents' house is a no-no.