Fear of silence and stillness.

 Since their minds have been conditioned to seek stimulation, people can't tolerate even the slightest moment of silence and stillness. They either hum something, make melodies by hitting objects, or openly complain about “how boring” the situation is—then proceed to open “prophetical topics” to talk about at length. They desperately need something that regularly stimulates their brains in order to feel “entertained.