Nearly 40 years ago Gary A. Steiner of the University of Chicago collected fascinating individual accounts of families whose set had broken--this back in the days when households generally had only one set: "The family walked around like a chicken without a head." "It was terrible. We did nothing--my husband and I talked." "Screamed constantly. Children bothered me, and my nerves were on edge. Tried to interest them in games, but impossible. TV is part of them."
In short, withdrawal symptoms. However, the good news is that only heavy users become addicted, and they actually enjoy TV less than those who watch it occasionally or in moderation. (via those liberal elitists at Plastic)