While `却` is a grammatical tool, its usage reflects a subtle aspect of Chinese communication style. Compared to the directness of the English “but,” `却` often softens the contrast, presenting it more as an observation of an unexpected reality rather than a direct refutation. For example, in Western culture, saying “He is very smart, but he is lazy” can come across as a strong, direct criticism where the “but” negates the positive quality. The Chinese equivalent, “他很聪明,却很懒” (Tā hěn cōngmíng, què hěn lǎn), can feel slightly different. The `却` focuses more on the surprising or ironic nature of the combination: “He's very smart, and yet, unexpectedly, he's lazy.” It's less of a confrontation and more of a nuanced observation. This indirectness and focus on the overall harmony of the statement, even when expressing a contradiction, is a common feature in Chinese discourse.
`却` is extremely common in both spoken and written Chinese. It adds a degree of sophistication beyond a simple `但是 (dànshì)`.