Facial expressions can trigger emotions: when we smile we feel happy, when we frown we feel sad. However, the mimicry literature also shows that we feel happy when our interaction partner behaves the way we do. Thus what happens if we express our sadness and we perceive somebody who is imitating us? In the current study, participants were presented with either happy or sad faces, while expressing one of these emotions themselves. Functional magnetic resonance imaging was used to measure neural responses on trials where the observed emotion was either congruent or incongruent with the expressed emotion. Our results indicate that being in a congruent emotional state, irrespective of the emotion, activates the medial orbitofrontal cortex and ventromedial prefrontal cortex, brain areas that have been associated with positive feelings and reward processing. However, incongruent emotional states activated the dorsolateral prefrontal cortex as well as posterior superior temporal gyrus/sulcus, both playing a role in conflict processing.