Why you shouldn't judge econometric results just in terms of P-values and R squared

Both The Undercover Economist (Tim Harford) and Freakonmics (Stephen J Dubner) have drawn attention to a Working Paper by Tatu Westling of the University of Helsinki which has the eye-catching title Male Organ and Economic Growth: Does Size Matter?.

I think this paper should help us to remember that P values and the size of R squared are not the only things to focus on when evaluating the results of an applied econometrics study.