I remember when reading Shakespeare's Sonnets for the first time. It was an English summer at a country pub in Hertfordshire. I sat outside, very much on my own, and drank in both the beauty of the words, and of course my beer. I had thought since then; that despite reading widely, that there would be no repetition of that experience.
But I have rediscovered it in Shelley’s work. The images he evokes are like mothers' milk to those of a freewheeling, unfettered imagination.

Take for example a few:

“Behold with sleepless eyes”

“Whilst me, who am thy foe, eyeless in hate”

“Black, wintry, dead, unmeasured”

“No change, no pause, no hope! Yet I endure.
I ask the Earth, have not the mountains felt?
I ask yon Heaven, the all-beholding Sun,
Has it not seen? The Sea, in storm or calm,
Heaven's ever-changing Shadow, spread below,
Have its deaf waves not heard my agony?”

“The crawling glaciers pierce me with the spears
Of their moon-freezing crystals;”

“Heaven's winged hound, polluting from thy lips
His beak in poison not his own, tears up
My heart; and shapeless sights come wandering by,
The ghastly people of the realm of dream,
Mocking me: and the Earthquake-fiends are charged
To wrench the rivets from my quivering wounds
When the rocks split and close again behind:
While from their loud abysses howling throng
The genii of the storm, urging the rage
Of whirlwind, and afflict me with keen hail.”

It is not the product of a good vocabulary, it is not verbose, and it is hard to put one’s finger on the structure. But then, why even try? There are many more qualified than myself to dissect the work of individual writers. The crux I think lies in seeing the power of mere words; that like blood stained drops from a fathomless chalice, stain the abyss of man’s frailty.