We provide evidence that the social norm (expectation) that adults work has a substantial detrimental causal effect on the mental well-being of unemployed men in mid-life, as substantial as, e.g., the detriment of being widowed. As their peers in age retire and the social norm weakens, the mental well-being of the unemployed improves. Using data on individuals aged 50+ from 10 European countries, we identify the social norm of work effect using exogenous variation in the earliest eligibility age for old-age public pensions across countries and birth cohorts.