Alluding to the difficulty in explaining the two opposing powers, the "dark side" and the Force, in the Star Wars movies, this paper focuses on the complex combination of negative and positive interactions among children who are best friends. Presented in question-answer format, the paper discusses research findings and needs related to two seldom explicitly asked questions. Question 1 concerns the definition of "the dark side of friendship," and focuses on fights, arguments, and annoying behaviors. This discussion explores the distinction between aggression and conflict, the impact of violations of assumed equality between friends, dominance versus leadership in friendship pairs, and violations of confidentiality or other violations of trust. The discussion maintains that additional research is needed regarding violations of trust, particularly using open-ended questions and direct observations of friends' interaction. Question 2 concerns the characteristics of friendships when the dark side is prominent, such as whether it is possible to have both positive and negative interactions on a frequent basis, the stability of such friendships, the role of popularity, and availability of other friends. Three additional questions are examined to illustrate the significance of research on negative interactions between friends: (1) what is the psychological and social profile of children whose friendships are high in negative interactions? (2) how does involvement in the dark side of friendship affect children's development? and (3) if children's friendships are high in negative interactions, should adults try to change those friendships? (Contains 17 references.) (KB)