Every vote creates winners and losers, opening a satisfaction gap between the two. At a time when concerns are high for democracy, we do not know what exactly leaves substantial proportions of voters—losers—dissatisfied with the system. This paper provides causal evidence for the cognitive dissonance theory, which points at unfulfilled winning expectations. With a difference-in-differences design around the Brexit referendum, it finds that the result caused an additional 3% decrease in the Remainers’ satisfaction if they were expecting to win the vote.