Oh, I'm missing out, no doubt. But missing out on what? When I was on FB, I was missing out--on my own life!
In my case, my family is not on FB. I talk to my family on the phone several times a week. I have friends who are on FB, but they know that they can email me or (gasp!) call me and we can talk face-to-face or at least on the phone if they live out of the area.
I'm much happier this way, and I'm not inclined at all to go back.