When I first studied figure drawing, I learned that hands were the most difficult to draw. Some students even asked the instructor to have the model hide her hands behind her back or otherwise conceal them so they would not have to deal with this difficult part of the human anatomy. Instead, I resolved to learn how to draw hands at least passably well.
It has been said that hands are expressive, even more so than the human face, because they can appear in many different configurations. Thus this series on the human hand.