The willingness of humans to take psychoactive drugs may reflect an unconscious optimism bias, where users focus on desired aims rather than actual consequences. A series of in-depth interviews will illustrate the experiences and explicit knowledge of recreational Ecstasy/MDMA users. Next an unpublished empirical study will be described, where four subgroups of Ecstasy users reported that MDMA loses its efficacy over time, while drug-related distress increased. As this cost-benefit ratio deteriorates, users take MDMA less frequently, before quitting permanently. The in-depth personal knowledge of experienced Ecstasy users might be useful for drugs education packages, since it could replace unconscious optimism with greater conscious awareness.