Who is Sally McLean from Crow Lake and what is their importance?

Sally McLean is the daughter of the local grocers. Sally has a crush on Luke but Luke refuses to become involved with her because he works for her parents and does not want to lose his job. However, Sally tells her parents lies about Luke and causes him to lose his job anyway. It is later implied that Sally tells lies that Luke is a homosexual. Katie reveals that Sally became pregnant by another local boy a short time after this and married him, only to get a quick divorce soon after.