here). To summarize my worries and criticisms briefly, my impression was and is: (1) that positive psychology puts too much emphasis on individual factors as determinants of behaviors and too little on situational factors, (2) that positive psychology emphasizes happiness too much as a criterion, (3) that positive psychology focuses too much on strengths and virtues as causes of human flourishing, and (4) that commerce and science appear to be too much intertwined.
There is a new article by well-known positive psychologist Robert Biswas Diener in which he reflects critically on positive psychology. He begins the article with a reference to the replication crisis which is happening in psychology (here is an explanation of that problem). Briefly put, the replication crisis is the problem that many of the effects which were found in original studies were not again found in replication studies and many of the effects which were found in the replication studies were weaker than the ones that were found in the original studies. Biswas Diener writes that this replication problem is especially troubling for positive psychology. For example, The Journal of Positive Psychology has consistently received low ratings with respect to replicability.
Biswas Diener also mentions that positive psychology is affected by "heavy commercialization". This is also my impression. There appears to be a great eagerness to bring findings and products to market which appear to lean on thin evidence, single studies which have not been replicated. The author mentions several examples of findings which have been presented by positive psychologists and which have later turned out to be (partly) wrong. He argues for more replication studies and for more caution in the presentation of findings.
I appreciate the fact that Biswas Diener is critical and self-critical. While I think that he is right in his two recommendations (more replication and more caution) I fear that he is still too mild about positive psychology. None of the four problems I mentioned in the first paragraph are dealt with (he does mention the problem of commercialization but I don't think he presents a solution).