Love one another and you will be happy. It’s as simple and difficult as that.

Mignon McLaughlin (1913-1983) American journalist and author

(Misattributed)

Cited by Wikiquote to The Complete Neurotic's Notebook (1980), but not found there, nor in The Neurotics Notebook (1965) or The Second Neurotic's Notebook (1966).

The actual source appears to be Michael Leunig (1945-2024), Australian cartoonist, poet, and artist.