What is interesting is how firmly fixed such internal preferences are.
By preference (which means by temperament), I have been a night owl since childhood; I am never alert - am barely human - in the mornings (not without an awful lot of strong coffee, first), whereas my mind works naturally at its best, and most creative, in the evenings.
When writing, (and when I was writing my book), my writing almost always occurred in the evening and at night (between the hours of 20.00-02.00); mornings were for editing - checking & confirming facts, checking sources, checking ease of readability, checking grammar, syntax, spelling.
Yes, of course, I can work in the morning, but I am not (naturally) at my best, despite society's preference for these hours.
In the mornings, (especially in winter, with its lack of natural light, and poor quality of light during daylight hours - I loved being abroad during winter), I always felt I was working against myself, whereas, during the afternoon and evening, I feel that I am working well within my own capabilities, for this is a time when things flow, (ideas, thoughts, speed of mental responses, even words...)