Billy Collins explained it.

Many.

Good writing becomes "great" in my eyes when some transcendent line grips me, and I am incapable of reading further until I have paused to cherish it. At 21 when I first read the last line of "The Dead" by James Joyce, I started keeping a journal just because I needed to record how I felt. Poetry's condensed, crafted lines have had such an effect on me even more frequently than prose.

I recognized the experience in a Billy Collins poem. Beautiful though it is, I don't know that this piece "stopped my heart," but it gave me the words I have recalled since whenever something has.

Old Man Eating Alone in a Chinese Restaurant

I am glad I resisted the temptation,

if it was a temptation when I was young,

to write a poem about an old man

eating alone at a corner table in a Chinese restaurant.

I would have gotten it all wrong

thinking: the poor bastard, not a friend in the world

and with only book for a companion.

He'll probably pay for the bill out of a change purse.

So glad I waited all these decades

to record how hot and sour the hot and sour

soup is here at Chang's this afternoon

and how cold the Chinese beer in a frosted glass.

And my book––José Saramago's Blindness

as it turns out––is so absorbing that I look up

from its escalating horrors only

when I am stunned by one of his gleaming sentences.

And I should mention the light

that falls through the big windows this time of day

italicizing everything it touches––

the plates and teapots, the immaculate tablecloths,

as well as the soft brown hair of the waitress

in the white blouse and short black skirt,

the one who is smiling now as she bears a cup of rice

and shredded beef with garlic to my favorite table in the corner.

The gleaming sentences that stun me, that impel me to look up from my absorption, stop my heart.