James Harden vs. Dwight Howard
For all of his career accomplishments and accolades, Dwight Howard will forever be known as that uncle who comes to visit, makes everything fun for a short time initially, but then overstays his visit and suddenly makes you count days until he leaves. That happened in his two previous stops (Orlando and Los Angeles), After the two worked together to win 56 games and take the Houston Rockets to the Western Conference Finals in the 2015 NBA Finals, the following season was a complete disaster.
It got to the point where the two players were barely on speaking terms, especially given how the team knew Harden was the centerpiece of the offense, but Howard insisted on being treated as such. That tumult led to former head coach Kevin McHale getting fired, and lending greater credence to the idea of Howard being a coach-killer.