柠檬不该羡慕西瓜的甜西瓜不该嫌弃柠檬的酸
[níng méng bù gāi xiàn mù xī guā de tián xī guā bù gāi xián qì níng méng de suān]
Lemon should not envy the sweetness of the watermelon; the watermelon should not look down on the sourness of the lemon. Metaphorically speaking, everyone has its own pros and cons so there should not compare one's shortcomings with others’ advantages