NBA bad boy Dennis Rodman had an up-close-and-personal look at Michael Jordan's legendary work ethic, when the two were teammates on the Chicago Bulls for three seasons in the 1990s.
And watching today's best player in the game - LeBron James - opting to sit out games to rest has the Hall of Fame forward steaming mad.
In an interview with CBS Sports, the flamboyant former All-Star ripped the Cavs superstar for doing what Jordan "never did" - taking games off to rest - and questioned James' accomplishments in today's game, compared to when Jordan played.
"You know what, LeBron's doing one thing that I always said that Michael Jordan never did," Rodman said.
"He never rested ... he played every game ... he played EVERY game. LeBron has the position to do this now, because they need him.
"The league needs him, that's why he's doing all this crazy s*** now, like bitching and complaining and all this [bull s***]."
Rodman said Jordan's offensive feats - leading the league in scoring 10 consecutive seasons - were also much more difficult than today, because of the physicality of the league.
Rodman should know, he was a key member of the Detroit Pistons "Bad Boys" teams that roughed up Jordan and the Bulls during their memorable playoff series.
"It's very easy to do what they define greatness [as now] - Michael Jordan did it when it was tough, really tough," Rodman told CBS. "And what'd he do? Lead the league in scoring 10 years in a row ... 10 years in a row, he led the league in scoring.
"Ten years in a row, back then, that was hard ... averaged like 32 points a game.
"That was hard back then, now it's easy. All these [expletive] triple-doubles ... back then when he was getting his ass whooped, I mean beat down every game.
"And then when he played against us [the Detroit Pistons], he said - guess what - 'I gotta go back in the gym'.
"And he got tough, He got tough and he got great ... and greater. So, that's it."
Jordan ran into several roadblocks early in his career, having to face Celtics teams with Larry Bird, Robert Parrish and Kevin McHale, and then facing Rodman's Pistons - both squads denying Jordan's path to the Finals.
He finally broke through in 1991, as the Bulls beat the Lakers for the first of their three consecutive titles.
After taking two years off and giving baseball a shot, Jordan returned to form during the 95-96 season, leading the Bulls, with Rodman by his side, to the start of another three-peat.