The western world is very different from those environments in which our species has roamed around for most of the time. Biology 101 tells us that with rapidly changing environments, (genetic) adaptation may fall behind rendering animals maladapted or “mismatched” to their environments. Some forms of human behaviour in the industrialised world might be similarly “mismatched”, and this idea is gaining in popularity in the medical and psychological sciences. In this talk, we try to argue the following points: 1) although the idea of “mismatch” provides a valuable perspective, it is often rather uncritically used; 2) the predictive ability of this perspective is often limited; even in rather clear cases such as obesity; 3) supposed cases of mismatch are often not backed up by appropriate empirical data; 4) this perspective is more valuable for the peculiarities of our body than of our mind. We conclude that the “mismatch” perspective is valuable in understanding (some) contemporary human behaviour, but that its use should be more stringent. Instances of surprising human behaviour shouldn’t uncritically be linked to mismatch. We further argue that maladaptive behaviour in contemporary populations is not so much a consequence of a “stone-age mind”, but rather of a mind containing fundamentally novel ideas.