Over the past decade, lawyers in Pennsylvania have gotten into trouble with the state's disciplinary board for offenses spanning from ripping off clients and being disrespectful to judges to arson, assault, and even homicide.

But the No. 1 cause of the hammer (or gavel) coming down on misbehaving lawyers is plain old lousy lawyering.

A review by The Legal of the Pennsylvania Supreme Court's Disciplinary Board records from 2006 to 2016 reveals that attorneys who are ineffective at practicing law—most commonly by neglecting cases, not communicating with clients, and general incompetence—made up the largest portion of those punished in nearly 640 instances, at 32 percent.