It is wise to apply the oil of refined politeness to the mechanism of friendship.

Colette likens friendship to a working mechanism—something durable but still subject to friction, wear, and occasional sticking. “Refined politeness” functions as oil: a small, deliberate layer of tact, restraint, and consideration that keeps intimacy from grinding into irritation or entitlement. The line suggests that true closeness does not excuse carelessness; on the contrary, friendships often last longer when warmth is paired with manners—when one continues to choose courtesy even with those who know us best. Colette’s image also implies a practical wisdom: politeness is not hypocrisy but a social technology that preserves affection by smoothing daily contact.