不用 (bùyòng) is a prime example of this. By saying “no need (for thanks),” a speaker subtly communicates that the favor was trivial and that the relationship is close enough that such formalities aren't necessary. It helps prevent the other person from feeling indebted (`人情 - rénqíng`). This can be contrasted with the more formal 不客气 (bú kèqi), which means “don't be a guest/stranger.” While both mean “you're welcome,” 不用 is often warmer, more casual, and more common among friends, family, and peers. It implies, “This was nothing for me, so don't even worry about thanking me.”