A strong inclination toward an activity that people like, that they find important, and in which they invest time and energy. Obsessive passion refers to a controlled internalization of an activity in one’s identity that creates an internal pressure to engage in the activity that the person likes. Harmonious passion refers to an autonomous internalization that leads individuals to choose to engage in the activity that they like.
Vallerand, R. J., Blanchard, C., Mageau, G. A., Koestner, R., Ratelle, C., Léonard, M., ... & Marsolais, J. (2003). Les passions de l'ame: on obsessive and harmonious passion. Journal of Personality and Social Psychology, 85(4), 756-767. doi: 10.1037/0022-35184.108.40.2066.