Noise
Continuous noise—like the background noise in big cities—is unnatural.
In our fascinating adaptability, we got used to it, but we shouldn't.
We need daily moments of absolute silence to function properly. But these days, silence scare us. We obsessively fill any moment of boredom with something. And there is always some thing (to watch, to read, to look up, to say, to think).
Remaining silent is neither slacking nor idling. A quiet and silent mind remains unshaken by phenomena—pleasant or unpleasant—and is the source of unimaginable power.