Franklin warns that humour is more capable of damaging an existing friendship than of repairing hostility. Joking with an enemy is unlikely by itself to overcome distrust or resentment, while a joke directed at a friend can cause embarrassment, offence or humiliation and weaken a relationship that previously depended on goodwill.

The saying does not imply that humour is generally harmful or that friends should avoid teasing one another. Much depends on tone, context and the people involved. Franklin’s broader point is that familiarity should not be mistaken for unlimited licence. A careless joke can cross a boundary quickly, particularly when it targets a person’s weakness or dignity. The proverb therefore encourages tact: humour may strengthen relationships when it is shared, but it can damage them when amusement comes at another person’s expense.