Pension policy in the UK and US is designed on the assumption that people make informed financial decisions, consistently invest in pensions and manage diverse portfolios. Deviating from this is often deemed irresponsible and irrational. However, this assumption overlooks uncontrollable factors like caring duties, employment breaks or income limitations. Even when individuals act as expected, unpredictable market shifts can hinder long-term planning. This book redefines deviations to “rational behaviour” as logical responses to a dysfunctional system. Challenging existing theoretical discussions and policy approaches, it proposes a fresh perspective on rationality when it comes to financial practices and policy.