I'm trying to overcome this tendency within myself, but it's a big battle.
Funnily enough, the times when I feel the most spontaneous shame for it is when I see my fellow human beings as pathetic-- including myself (usually myself in the past). Then I genuinely feel for them and feel bad I ever scorn them.
I had a friend once who told me about a friend of her own, who had adopted two little girls from a background of extreme poverty. She said that, the first night she put them to bed, she noticed as they were sleeping that they were both holding onto the shiny wrapping paper in which she had given them some kind of chocolates earlier. They'd never owned anything and so they held onto this. I found this story very affecting, and illustrative of the human condition.
It reminds me of this passage from Chesterton's Manalive, which I've only read once:
"Why are children not afraid of Santa Claus, though he comes like a thief in the night? He is permitted secrecy, trespass, almost treachery—because there are more toys where he has been. What should we feel if there were less? Down what chimney from hell would come the goblin that should take away the children's balls and dolls while they slept? Could a Greek tragedy be more gray and cruel than that daybreak and awakening? Dog-stealer, horse-stealer, man-stealer—can you think of anything so base as a toy-stealer?'
"The burglar, as if absently, took a large revolver from his pocket and laid it on the table beside the decanter, but still kept his blue reflective eyes fixed on my face.
"`Man!' I said, `all stealing is toy-stealing. That's why it's really wrong. The goods of the unhappy children of men should be really respected because of their worthlessness. I know Naboth's vineyard is as painted as Noah's Ark. I know Nathan's ewe-lamb is really a woolly baa-lamb on a wooden stand. That is why I could not take them away. I did not mind so much, as long as I thought of men's things as their valuables; but I dare not put a hand upon their vanities.'
It also reminds me of this poem by Coventry Patmore, which I can only read through tears:
My little Son, who look'd from thoughtful eyes
And moved and spoke in quiet grown-up wise,
Having my law the seventh time disobey'd,
I struck him, and dismiss'd
With hard words and unkiss'd,
His Mother, who was patient, being dead.
Then, fearing lest his grief should hinder sleep,
I visited his bed,
But found him slumbering deep,
With darken'd eyelids, and their lashes yet
From his late sobbing wet.
And I, with moan,
Kissing away his tears, left others of my own;
For, on a table drawn beside his head,
He had put, within his reach,
A box of counters and a red-vein'd stone,
A piece of glass abraded by the beach
And six or seven shells,
A bottle with bluebells
And two French copper coins, ranged there with careful art,
To comfort his sad heart.
So when that night I pray'd
To God, I wept, and said:
Ah, when at last we lie with tranced breath,
Not vexing Thee in death,
And Thou rememberest of what toys
We made our joys,
How weakly understood
Thy great commanded good,
Then, fatherly not less
Than I whom Thou hast moulded from the clay,
Thou'lt leave Thy wrath, and say,"I will be sorry for their childishness."