3. Karl Malone
We're not going to mention Karl Malone's off-the-court behavior, as it's a serious issue and this is about on-the-court nonsense. So, when you take away the gross misconduct off the court, you're left with a pretty unforgivable move on the court. In the eyes of fans, no greater sin can be committed during a player's career (aside from actual crimes) than that of leaving to ring chase especially when you've been around for 20 years.
That's what Malone did, ending a 20-year relationship with a club that gave him everything, including shelter from his behavior. Malone left in 2003 to go chase a ring with the Los Angeles Lakers. He joined Shaquille O'Neal, Kobe Bryant, and fellow new addition Gary Payton to make up one of the most star-studded groups in NBA history.
It was also one of the worst-performing super teams of all time. The Lakers were carried by Bryant, with O'Neal, and Malone looking like shells of themselves. The team fell to the star-less Detroit Pistons, and Malone quietly retired after.