En inglés: «And my personal favourite: The only normal people are the ones you don't know very well».
Fuente: Gehart, Diane R. Theory and Treatment Planning in Counseling and Psychotherapy. 2ª Edición. Editorial Cengage Learning, 2015. ISBN 9781305533875, p. 95. https://books.google.es/books?id=xqCKBAAAQBAJ&pg=PA95&dq=The+chief+danger+in+life+is+that+you+may+take+too+many+precautions.+Alfred+Adler&hl=es&sa=X&ved=0ahUKEwjw7qyy37vgAhUEuRoKHbTWA0UQ6AEIMjAB#v=onepage&q=The%20chief%20danger%20in%20life%20is%20that%20you%20may%20take%20too%20many%20precautions.%20Alfred%20Adler&f=false En Google Books.