Celtics win ugly vs. Pascal Siakam, Pacers: ‘We’ve grown in a lot of ways’

BOSTON — Entitlement, Joe Mazzulla detests it. He knows when his team coasts to another easy win, everyone will think the coast is clear at the top of the league. They look up the standings and just see blue sky, instead of the rocky cliffs below the summit. But you don’t dwell on the mountaintop. The air is too thin up there. As teams like the Indiana Pacers make big trades to move toward serious contention, reality sets in. Each team in the NBA has a short window to win a title. It’s that brief plateau on a franchise’s bell curve of success where player development, experience and expectations intersect. Tuesday’s 129-124 win over the Pacers was a reminder of…