While creating value in open innovation (OI) requires knowledge sharing, appropriating value in OI entails some closedness and protectiveness. Hence, tensions between generating and appropriating value, known as the paradox of openness, may emerge in OI collaborations. Such tensions have been scarcely explored at the micro-level, even though it is a crucial piece to fully grasping the paradox of openness. Our study bridges this gap by examining individuals’ affective responses to tensions and their outcomes in OI, thereby capturing the microfoundations of the paradox of openness. The study adopts an inductive qualitative approach and delineates various micro-level coping mechanisms that build on figurative language and humor. Accordingly, our study reveals hidden tolls of the paradox of openness, highlighted by the dominance of destructive rather than constructive affective responses. These hidden tolls illuminate a “dark side” of OI, which taps into the potential failures and high costs of opening up.