Failure to Learn and Clarify Your Clients' Expectations.
Clients have all sorts of expectations of their lawyers.
Some expect their lawyers to solve any and all problems they've accumulated since puberty. Some expect their lawyers to exact retribution upon their opponents, enemies and other lawyers. Some expect their lawyers to be available for counseling and hand-holding 24 hours a day. Many clients' expectations are unrealistic. Some may involve illegal activity or violation of the Rules of Attorney Conduct.