It means that something is outrageous and unreasonable. According to Zhihu's information, the return performance is usually to arrange the masses to appear in the performance; Lemon trees are often propagated by sowing or grafting, and can be cultivated all year round, with high nutritional value. Their fruits have the functions of quenching thirst, promoting fluid production, whitening skin, removing fat and appetizing. Peel the fruit and dry it in the sun to make traditional Chinese medicine tea, which is fragrant, sweet and sour, and is known as the king of relieving summer heat. These three application scenarios all have illogical and unexpected meanings in work and life, so "returning lemons" can also be used to describe some very illogical and unexpected things.