When the NBA expanded to six divisions from four in 2005, it retained a rule that guaranteed each division winner a top seed in the conference. Therefore, a team that won its division could finish no lower than third, even if it had a worse record than another team that didn’t win its division.
That led to some interesting jockeying for playoff seeding in 2006, most notably when the Los Angeles Clippers may or may not have deliberately lost to the Memphis Grizzlies in the last week of the season to fall to No. 6 in the West. As a result of that loss, the Clippers played the Northwest champ Denver Nuggets in the first round, who they beat handily, instead of the Dallas Mavericks, who finished 16 games better than Denver and eventually advanced to the NBA Finals.
Needless to say, that was bad optics for the league, which immediately changed its postseason rules to only guarantee a division winner a top-4 seed in the conference, and not even homecourt advantage in the first round if the fifth seed had a better record.
That worked mostly well, but also failed to solve the league’s issues. Over the next nine postseasons, five division winners received the No. 4 seed despite another team in the conference having a better win-loss record. The straw that broke the camel’s back came in the 2015 playoffs when the Portland Trail Blazers earned the No. 4 seed at 51-31 while two teams finished four games better, the Grizzlies and the San Antonio Spurs.