Do I really care about my cousin's vacation at Disneyland and pictures of his bratty kids? No!
Do I really want people I went to high school with 30 years ago to find me? No!
Do I really want to put personal information about myself online so my employer (and potential future employers) can find it? Hell no!
There are about a hundred other good reasons for not using Facebook.
As a legislative district chair, I use Facebook for meeting announcements. People I know have gotten elected to the state legislature with the help of Facebook and other venues.