Woman in the grocery store, crowding hard to the right, as if to shove you more quickly through the checkout stand.
Man in the organic food store, racing his shopping cart through the aisle to beat all others to the checkout line. Earlier he and his cart blocked for some time the single shelf you were interested in.
Dog droppings on the sidewalks. People are unwilling to walk their animals two blocks to the park. Instead they use the shopping center for a toilet.
At home, the neighbors play repetitive music, loud, the same song seemingly on auto-repeat, hours at a time. Ba-DUM-da-bum.
The stress of crowding.
Too many souls for one world. Too many, thrown too closely together.
Agoraphobia.