The surest way to ruin a man is to teach him to regard the world as his friend.

This line is commonly presented as a cautionary aphorism about naivety and misplaced trust in society at large, implying that expecting goodwill from the world can leave someone unprepared for disappointment or exploitation.

It suggests that treating the world as inherently benevolent can weaken a person’s judgment and resilience; a more guarded, realistic stance is portrayed as protective.