When George's mother, Mrs. O'Malley, comes into the hospital for surgery, Callie decides to come out as bisexual and tells her that she has a baby and is really happy now. Mrs. O'Malley's teary smile when she asks if she has any pictures of Sofia goes a long way towards fixing the Tear Jerker of her own mother's disapproval of her getting married to another woman and saying they're not a real family.
Derek's marriage proposal to Meredith in "Elevator Love Letter"
Meredith: "I don't know what it's like to have a father. But I do know what it's like to have a sister. And it's good."
In season 9 the hospital is renamed the Grey Sloan Memorial Hospital.
Jackson congratulating April on winning Chief Resident. Not only is he the one person to do so but he is truly happy for her. Made even more heartwarming when they realise they are now happy after surviving the shooting and grieving for their murdered friends.
In Season 11, Owen gives a You Are Not Alone speech to a veteran who was living out of her car. The veteran, Melissa, is embarrassed since she never saw combat and only fixed computers in the Green Zone.
Season 12's "Mama Tried" had a tribute to Prince two weeks after his death. The song "Nothing Compares 2 U" plays. Shonda Rhimes said on Twitter how Prince's estate allowed the show to use the music to salute the artist.