When I worked as a Customer Support Manager for Oracle, my boss taught me that perception is reality.  What you know to be true and what others know to be “true” are not always the same thing, and could differ far more than we think.  This lesson came about because I had been a Technical Support Analyst and had gotten promoted to Manager. So the people I had been friends with were now my employees, and I had to draw a fine line between friendship and a professional relationship so that the perception of possible favoritism towards my team was as small as possible.  There was never going to be a way to remove that judgment entirely, and I worked hard to show everyone I worked with how valued they were.