Rasheed Wallace had a productive career, earning four All-Star selections and winning an NBA title.

He also made a few enemies along the way.

One such adversary was referee Danny Crawford, who retired in 2017 after 31 seasons as an NBA official. The two engaged in a number of verbal spats during their time together in The Association, which even included an interesting incident after Wallace and the Boston Celtics lost to the Los Angeles Lakers in Game 7 of the 2010 NBA Finals at Staples Center.

Crawford recently explained on NBC Sports Boston’s “Celtics Talk Podcast” that Wallace tried to enter the referees’ locker room, prompting security to intervene. While Crawford heard Wallace, who just wrapped up his only season with the Celtics, wanted to apologize, the longtime ref had no interest in talking out any differences. Their relationship simply was too tumultuous.

“If you think about Rasheed Wallace’s relationship with referees over the years — it was impossible,” Crawford said. “He was the most difficult man in the world to referee, to deal with. It was impossible.”

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Sometimes, things are said in the heat of battle that ultimately get resolved. It sure sounds like Crawford still has no time for Wallace, though, calling him the “most difficult individual” he dealt with in his officiating career.

“It was just I knew what he was all about,” Crawford said. “And he was just a difficult guy and he defied authority and no matter what I said to him — I used to try to massage his ego with child psychology and it never worked, in my whole career. So, Rasheed Wallace and I, no conversations.”

It wouldn’t be surprising to learn that other NBA referees hold a similar opinion, as some of the lasting images of Wallace’s career involve him arguing with officials.

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