If there’s another X-factor that Tatum believes shouldn’t be overlooked in assessing the Celtics’ title chances, it’s head coach Joe Mazzulla. “He’s the best coach in the NBA, even though he’ll never admit that,” Tatum says. Mazzulla’s brilliance as a play caller is sometimes overshadowed by his habit of dropping unintentionally hilarious one-liners in interviews, which Tatum admits the locker room gets a kick out of. “We laugh [about it],” he says. “Like, we love to watch his press conferences.” I ask Tatum about his favorite thing Mazzulla has ever said to him. “He always tells me that he loves me,” he shares. “He’ll say it on practice days or in the middle of a game during a timeout. It’ll be the third quarter of a playoff game, a very intense atmosphere, and he’ll say ‘Just want you to know I love you, man.’”