I suppose it it tempting, if the only tool you have is a hammer, to treat everything as if it were a nail.

—Abraham Maslow, The Psychology of Science: A Reconnaissance (1966)

This is a common quote, sure—"To a person with a hammer, everything looks like a nail". While reading Michael Watkins, The First 90 Days: Critical Success Strategies for Leaders at All Levels (notes), there was a reference to this line by Abraham Maslow, which is, according to the author, the original.