1. Profit means earnings above what could be earned in your next best opportunity. Tavern owners only earn economic profit after they meet all costs of doing business including paying themselves a salary equal to what would be earned in their next best job. While people with extraordinary skills, talents, and a great deal of education may well own bars, such skills and talents and training aren't necessary so that the average salary of bar owners in their next best opportunity may be about equal to average earnings in the city. Lawyers, on the other hand, almost certainly have 7 or more years of education after high school (4 years college + 3 years law school). That same amount of training would almost certainly guarantee them higher earnings even if they weren't lawyers so zero profit will still allow them to earn a higher income that the typical tavern owner.