对你微笑纯属礼貌对你微笑纯属可笑
[duì nĭ wēi xiào chún shŭ lĭ mào duì nĭ wēi xiào chún shŭ kĕ xiào]
On the surface, it means that a smile given to you is purely out of politeness rather than from the heart, further emphasizing such polite action seems ridiculous or not genuine.