The appearance and behavioral design of life-like agents used in human-computer interaction is important to establish an intuitive and emotional relationship between a user and an agent. This paper analyzes the impressions of a "sidelong glance" as one of the combinatorial nonverbal behaviors that comprises gaze, head orientation, and facial expression. Through the analysis, we show that the "sidelong glance" conveys the specific impression of "friendliness" and "dominance" on users. We also show that an "attractive face" is friendlier than the "average face" and that a "smiling face" emphasizes friendliness. Finally, on the basis of our experimental results, a comprehensive affection model of agent behaviors is proposed. The model will contribute to designing the appearance and behaviors of interactive life-like agents.