This paper discusses (i) the usefulness and (ii) the clarity of the concept of arousal. In discussing its usefulness, I argue that we can explain some key “arousal effects” without relying on the concept of arousal. To do so, I consider the role of the appraisal of affective relevance as a process mainly subserved by the amygdala and explaining emotional effects on attention, memory, and learning. Then, with respect to the clarity of the concept of arousal, I use the componential approach to emotion to suggest that further research may investigate whether the umbrella term “arousal” covers five different concepts (energy, sympathetic nervous system activity, intensity, strength, and salience), each corresponding to a specific component of emotion.