Point Out The Cliff
Communication can change people's direction
People are motivated to change in different ways.
For some people, they will confidently continue on a course of action, even if you suggest that they change. One of the most effective strategies with folks like this is to “point out the cliff.”
“If you keep treating team members like that, you’ll never get another promotion.”
“If you don’t incorporate the client’s suggestions, they will no longer be your client.”
“If you don’t stop cussing people out, you’ll be fired.”
To get through, bottom-line it in a single sentence. “If you keep doing X, this bad thing will happen.” Long-winded explanations about how other people feel when they engage in the behavior will be dismissed. Point out the cost to THE INDIVIDUAL themselves.
If you get through to them, expect to see them startle (possibly wide-eyed and uncharacteristically silent). They might not immediately change course (they might not want to give you the satisfaction of having corrected them), but they may make significant efforts behind the scenes to course-correct.