Since Coach K was brought up, here is some stuff I can come up with right away...
He was a Bobby Knight disciple and was just as demanding and opinionated as Knight, but was smart enough to avoid having that be his public persona. Some would call it hypocrisy.
He taught every Duke player how to flop and they did it ALL the time. Many of his players also played dirty.
He was so self-absorbed that he couldn't stand it when he lost games to Rick Pitino and other flawed people, so he totally compromised the academic standards of Duke and jumped into the "one and done" concept with both feet.
The national media fawned over him and he seemed to encourage it.
Duke got favorable draws in the NCAA tournament year after year, so the favoritism was pretty blatant.
On the plus side, he did a lot of charity work, but when you are making tons of cash, that can be viewed as building an image... but you have to assume he was trying to help.
The difference between how people view Bobby Knight and Coach K has always annoyed me, because they were very similar.