Personalized Worlds Greatest Pappy Youth Long Sleeve T-Shirt. Worlds greatest pappy in text with the earth in place of the letter O in the word world is a unique gift design for grandfathers on birthdays, holidays and Father's Day. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)