W.H. Auden, from his “Reading” essay in The Dyer’s Hand:

Between the ages of twenty and forty we are engaged in the process of discovering who we are, which involves learning the difference between accidental limitations which it is our duty to outgrow and the necessary limitations of our nature beyond which we cannot trespass with impunity. Few of us can learn this without making mistakes … When someone between twenty and forty says, apropos of a work of art, “I know what I like,” he is really saying “I have no taste of my own but accept the taste of my cultural milieu,” because, between twenty and forty, the surest sign that a man has a genuine taste of his own is that he is uncertain of it.

Lorrie Moore, from her novel Anagrams (via Vintage & Anchor):

Basically, I realized, I was living in that awful stage of life from the age of twenty-six to thirty-seven known as stupidity. It’s when you don’t know anything, not even as much as you did when you were younger, and you don’t even have a philosophy about all the things you don’t know, the way you did when you were twenty or would again when you were thirty-eight.

W.H. Auden, “The Sea and the Mirror”:

Well, who in his own backyard
Has not opened his heart to the smiling
Secret he cannot quote?
Which goes to show that the Bard
Was sober when he wrote
That this world of fact we love
Is unsubstantial stuff:
All the rest is silence
On the other side of the wall;
And the silence ripeness,
And the ripeness all.

W.H. Auden, “As I Walked Out One Evening”:

‘I’ll love you, dear, I’ll love you
     Till China and Africa meet
And the river jumps over the mountain
     And the salmon sing in the street.

‘I’ll love you till the ocean
     Is folded and hung up to dry
And the seven stars go squawking
     Like geese about the sky.

And:

‘O plunge your hands in water,
     Plunge them in up to the wrist;
Stare, stare in the basin
     And wonder what you’ve missed.

‘The glacier knocks in the cupboard,
     The desert sighs in the bed,
And the crack in the tea-cup opens
     A lane to the land of the dead.

My favorite quote from The Shakespeare Miscellany, by the way, is Auden’s sublimely pithy remark on Hamlet: Be suspicious of people who want to play this part.

A repeat from a while ago: Auden, from “Vespers”, 1954:

In my Eden we have a few beam-engines, saddle-tank locomotives, overshot waterwheels and other beautiful pieces of obsolete machinery to play with: In his New Jerusalem even chefs will be cucumber-cool machine minders.

Cucumber-cool machine minder = my job title. Hiss, put it on my luggage.