“…On the one hand, overconfident consumers “act presumptuously” (Pillai & Hofacker, , p. 263; i.e., engage in actions that are too difficult to perform), as they think they have enough knowledge to handle these actions. Acting presumptuously might lead to inappropriate purchase decisions (Alba & Hutchinson, ; Hansen & Thomsen, ; Kidwell, Hardesty, & Childers, ), risky investment decisions (Hadar, Sood, & Fox, ), a lack of flow state of mind (i.e., an optimal state of mind where there is a deep engagement with a consumption task [Csikszentmihalyi, ]; Pillai & Hofacker, ), frustration (Pillai & Hofacker, ), and satisfaction with the variety of personalizable product‐attribute options (i.e., those attribute options that are evaluated based on personal preferences, such as mobile phone color; Puligadda et al., ). On the other hand, this paper suggests that underconfident consumers act timidly (i.e., engage in actions that are too easy to perform) due to the fact that they think they do not have enough knowledge to engage with challenging actions.…”