The mind can drift. Hollow eyes peering at nothingness. The complexity of audio visuals from a CRT require continued sustained concentration to capture a fraction of the subtleties of what's going on. Sarcasm can be overlooked without embarrassment because transmission continues. Viewer keeps to self, unnoticed.
Laughter is synthetic, audio cues tell one when to smile.
Advertisements subconsciously suggest what is worth ones time and money, subtly taking advantage of this stupor. Transmission media provide this comfort zone. Smoking provides a similar escape. When puffing or pulling one can take a minute to think, collect oneself or ignore someone else. Marketing markets cigarettes for the thinking man.