棉花糖抹不去咖啡的苦
[mián huā táng mŏ bù qù kā fēi de kŭ]
The contrast between the sweet, fluffy candy (marshmallow in English) and bitter coffee symbolizes something pleasant unable to eliminate or cover the more profound bitterness of life. It implies the inability of fleeting happiness or sweetness to resolve deeper issues or long-term suffering.