柠檬不羡慕西瓜的甜
[níng méng bù xiàn mù xī guā de tián]
'Lemon does not envy the sweetness of watermelon'. Here 'lemon' can imply oneself or a specific object/person/idea while 'watermelon's sweetness' can be understood to represent others’ success, happiness etc. It indicates a kind of peaceful and contented mindset, suggesting no unnecessary comparison between two distinct entities.