Source, in full
Called "Baruch's Observation" in The Complete Murphy's Law : A Definitive Collection (1991) by Arthur Bloch, such statements have also attributed to, Michael Polanyi, and Mark Twain; see the Wiktionary page for this statement for more details.
Notes from Wikiquote
Abraham Maslow, The Psychology of Science : A Reconnaissance (1966), Ch. 2, p. 15.
Variants
I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail.