Thinking is the hardest work there is, which is probably the reason why so few engage in it.
The High School Teacher, Vol. XI, 1935.
![Thinking is the hardest work there is, which is probably the reason why so few engage in it.](http://cdn.myquotes.org/images/henry-ford/thinking-is-the-hardest-work-there-is-which-is-probably-the-reason-why-so-few-engage-in-it.jpg)
Thinking is the hardest work there is, which is probably the reason why so few engage in it.