Hard to win in the NBA when the best player is on the other side of the court. Always has been, always will be. SGA is just filthy.
I love the Celtics roster, but in the playoffs it can be a problem that against a lot of teams we won't have the best player on the floor. 76ers (Embiid), Bucks (Antetokounmpo), Pacers (Haliburton), Nuggets (Jokic), Thunder (SGA), Clippers (Leonard).