I use facebook to feel connected to people I know and to the world. I had to deactivate mine for a couple days due to a group that was trying to attack me and get info on me and people in my life in a public forum, and those 2 days without facebook drove me crazy. I felt irritated because I felt like maybe I was missing out on something. Most of my fb activity is just lurking peoples updates and occasionally communicating people privately. In reality, I'm not missing out on much but I feel like I am whenever I am away from it for more than a day.