The right to happiness has recently gained relevance in Brazil s Constitutional Law debate, mostly because of two Proposed Constitutional Amendments aiming to constitutionalize such right. Even though such amendments did not pass, most legal scholars have adopted the position that the right to happiness is implicit in our legal system. However, this might not be beneficial for the legal system, when taken into consideration the recent finding from the fields of experimental philosophy and behavioral psychology. Research from the former demonstrates that the ordinary concept of happiness, besides capturing the psychological states of an agent, captures – unexpectedly – moral evaluations; while research from the latter demonstrates that people, systematically, fail in predicting and making decisions (if they had predicted) that maximize their happiness. From this point, the research attempts to prove three hypotheses: (1) the concept of happiness, because of its psychological and evaluative components, is highly variable due to the moral conceptions of each subject, what might implicate in negative results for cases based on its grounds; (2) The different types of biases that affect people s decision on what makes them happier might lead to results contrary to the expected in legally relevant cases; (3) Due to the limitations imposed to all people, the insertion of the right to happiness might be extremely harmful to the legal system. With the use of a bibliographical and experimental methodology, it was possible to prove the first two hypotheses presented, as well as to find reliable grounds that point toward the correctness of the third. Therefore, the work concludes that, at least in Brazil s current legal scenario, it is not worth constitutionalizing the right to happiness if this means taking the risks of producing possibly disastrous results for the legal system.