人走茶凉心慌不忘
[rén zŏu chá liáng xīn huāng bù wàng]
The saying conveys the bittersweet feeling of farewell. When guests leave (people gone), the served tea turns cold and the heart feels uneasy. But it also emphasizes the lingering memory that stays with you, not to be forgotten despite the sadness of parting moments.