In this article the objective dimensions of social exclusion (unemployment, low income, low social and/or political participation) and the subjective ones (perceptions on the phenomenon) are compared in order to set up an explanatory frame to analyze these two dimensions. It is based on an analytical cross sectional study in which a survey was applied to people from different social strata. Related to the objective dimensions it was found that more than 50% of the population is socially excluded: they suffer multiple deprivations that prevent them from participating in the social life. In contrast a smaller percentage of people perceived themselves as socially excluded. It is possible that the divergence between objective and subjective dimensions of social exclusion -which is also found when assessing poverty- is due to a process of collapse of expectations, drawn from insurmountable social barriers faced. So, constructs such as happiness and optimism, which are frequently used to measure welfare, demand a critical reading of results and notions used in context.