Team devotion can be torn down when corrosive behaviours breach group morale. A gnawing sense of unease grows when hardworking team members see unethical practices, cutting corners, or unfair favouritism and nothing is done about it.
Many leaders step aside when they see these behaviours because they don't want to create unrest. It's easier to turn a blind eye than to address the real issue.
The result is a dent in team congruency that knocks down morale. Unethical or Difficult people are doing these things for a reason: they get something out of it. For instance, being ethical and doing the right thing takes time and effort. If difficult people can cut corners or distort the truth, they can get more work done with less effort.
What leaders may not recognize is the toll this takes on team morale.
The reason corrosive behaviours chip away at morale is because the people, who are dragging others down, get away with it. Some would argue that the leaders that don't address these unacceptable practices are collaborating in the faulty practice.
To boost morale, great leaders must clearly define what behaviours are not open to compromise. The more transparent, accountable and well defined acceptable and unacceptable behaviour is the better.
After all, work should not define the person, the person should define their work. However, everybody's definition is different. Certain behaviours are ok, while others will drag down morale.