Losing Horford just sucks; he has been my favorite Celtic since he first started playing here. I think he did so much for this team during his time in Boston and they are going to miss him dearly, arguably more than Kyrie. There were so many little aspects of the game he nailed down; whether it was setting screens, contesting shots without fouling, covering up for other defenders' mistakes, nimbly switching onto guards, spacing the floor, firing outlet passes or tossing perfect bounce passes from the high-post, he did so much for the team that wasn't always reflected in how many points he scored or rebounds he grabbed.
That kind of made him more fun to root for; appreciation of Al Horford was like a basketball litmus test, if you thought he was overrated because he didn't score 20 ppg, it was a sign you didn't understand just how important different aspects of the game were. Part of the fun with Horford was that his game exposed blowhards like Lou Merloni, who couldn't be bothered to appreciate the subtle parts of what makes a great player great.
Horford didn't have highlights the way LeBron James, Giannis or Steph Curry did, but he has tons of memorable plays. Setting a high screen for IT and rolling to the three point line, which either cleared the lane for the little guy to attack the basket, or made slow-footed big men pay for not getting out on him. Or feeding Brown/Tatum from the elbow on cuts to the basket. Or rotating over as the help defender and forcing a tough shot when a teammate got beat.
His success over Embiid was particularly enjoyable. Embiid got more buzz, was bigger, stronger and louder. Yet, like Russell vs Chamberlain, the quiet, no-nonsense Horford puzzled Embiid with his quickness, decision making, and above all else, intelligence, that gave Boston an edge against Philly. Horford blowing past a gassed Embiid as he tried to get out to contest a three in the playoffs is probably the enduring moment of Horford's time in Boston.