péngyou shuō "bùyòng dài dōngxi" shí, yǒushí shì zhēn bùyòng, yǒushí shì kèqi

朋友说“不用带东西”时，有时是真不用，有时是客气。

When a friend says "no need to bring anything," sometimes they really mean it, and sometimes they are just being polite.