Post Keynesians define conventions as creeds shared by individuals who use them to ground their expectations. Economic policymaking plays a major role in the development of conventions. Thus, this article analyses Brazil’s fiscal and monetary policies over 2011-2017. First, it shows how the monetary policy over 2011-2014 wasted the opportunity to establish a lower base rate in Brazil, what we call ‘the mistakes of the past’. Second, it argues that the austerity policy implemented after 2015 formed the convention that public investments are not needed to boost private investments; this is what we call ‘the loss of future opportunities’.