The problem with psychology is lack of specificity. The discipline really could be split and absorbed into both philosophy and biology, but the intersection is important and certainly interesting, thus the field. Nevertheless it suffers from this wishy washiness, either ending in abstract conclusions that could be reached philosophically or in concrete conclusions that could be reached biologically (history actually also suffers from this problem, that it could be subsumed into other disciplines, history of politics in politics, history of theology in theology). Of course, life is wishy washy itself and to a certain extent, results direct and consistent may or may not provide salient insights into the question at hand, and surely psychological inquiries often fit this mold - indeed results that encapsulate the flux and inconsistency of life may be psychology's greatest value.

Lack of specificity in psychology often emerges in the form of experimental data. You can find experimental results that both refute and support a psychological hypothesis and the solution of narrowing the hypothesis has the lackluster effect of producing hypotheses of less and less interest or import. The bane of psychology may simply be that its field hovers over the mind which is the least understood, least quantifiable, and possibly most abstract thing to attempt to subject to science. We should by no means abandon psychology, rather we should further encourage the pursuit of psychological questions and the field itself, but psychology does suffer from this lack of specificity, and as such, must further become a highly interdisciplinary, interdependent field.