What does it mean when someone says that a person is a piece of work?

When someone refers to a person as "a piece of work," it typically means that the individual is complex, challenging, or difficult to deal with. This phrase can carry a negative connotation, suggesting that the person has quirks, flaws, or behaviors that make interactions with them particularly taxing or problematic. It can also imply that the person is unique or noteworthy in some way, but often emphasizes the challenges they present.