the feeling is mutual

You and I feel the same way. Strictly speaking, mutual means “reciprocal.” When Jack says, “I can’t stand your affected accent,” and Jill replies, “The feeling is mutual,” Jill is saying that she feels the same way about Jack’s accent. Nevertheless, in the course of the twentieth century, when this expression became a cliché, it was—and still is—often misused, in that it is used to describe a common or shared feeling about something or someone else. For example, when Jill says, “I think the president is marvelous” and Jack says, “The feeling is mutual,” he really means he thinks the same as she, but no reciprocity is involved. (This misuse has an honorable ancestry; Dickens made the same mistake in the title of his novel Our Mutual Friend.) See also mutual admiration society.