Facial expressions of emotion can function as social (dis-)incentives, depending on the perceiver’s implicit affiliation or power motives. Specifically, submissive vs. dominant displays are supposed to be positive vs. negative social incentives for power-motivated perceivers, whereas friendly vs. hostile displays are supposed to be positive vs. negative social incentives for affiliation-motivated perceivers. Past research has demonstrated corresponding influences on attention orientation, action selection, and implicit learning. We present two studies, in which we tested the impact of emotion emojis embedded in a cognitive task on the effort that participants mobilized during task performance. Implicit power and affiliation motives were measured with the Picture Story Exercise, which quantifies the content of imaginative stories written in response to ambiguous picture cues. Effort was operationalized as sympathetically-driven cardiovascular reactivity. Results revealed that highly power-motivated participants showed less cardiovascular reactivity when dominant displays were shown after successful trials (Study 1). Moreover, highly affiliation-motivated participants showed stronger cardiovascular reactivity when friendly displays were shown after successful trials (Study 2). These studies demonstrate that dominant facial expressions lead to disengagement in terms of reduced effort if individuals are highly power-motivated. Furthermore, friendly facial expressions lead to increased task engagement in terms of effort if individuals are highly affiliation-motivated. The same facial expression of emotion (e.g., smile) may not motivate everybody in the same way: It depends on the person’s prevalent implicit social motive and the corresponding (dis-)incentive quality of the emotional display.