Work Efficiency and Likings

I have noticed that whatever I do according to my likings (including everything except food and drink, also sex), increases my work efficiency in everything. And that whatever I do against my likings decreases my work efficiency. In this book I have generalized this observation to the scientificial language so that all could apply it to their own life and to their own work. In the book I explain how the different human functions interconnect and how feelings are rational in the light of the theory of evolution.