Marian Anderson's ever-uplifting "He's Got the Whole World in His Hands":
https://m.youtube.com/watch?v=MRGZrv0Hl6k
[In case anyone is somehow not familiar with Marian Anderson:
https://en.wikipedia.org/wiki/Marian_Anderson ]
PS, this, too -- non-famous flight attendant's parting words on arriving at BWI airport from MHT, which drew big smiles and applause from the passengers: "Thank you for flying Southwest. And please remember to be nice to one another."