Nico Harrison's worst decision as the Dallas Mavericks' GM was, by far, sending Luka Donu010diu0107 to the Lakers. He made a few other questionable moves during his years in Dallas, including one after the Donu010diu0107 trade, when he traded Quentin Grimes to the Sixers for Caleb Martin. It could never get worse than the Donu010diu0107 trade, but Harrison managed to torment Mavericks fans even more.
Grimes was on another level in the second half of the 2024-25 season, but that was for a depleted Philadelphia squad that didn't have anything to play for. Or that's what Dallas fans told themselves.