Treading on dreams

Sir Ken Robinson, in this TED talk, quotes W.B. Yeats:

“Had I the heavens' embroidered cloths,
Enwrought with gold and silver light,
The blue and the dim and the dark cloths
Of night and light and the half-light,
I would spread the cloths under your feet:
But I, being poor, have only my dreams;
I have spread my dreams under your feet;
Tread softly because you tread on my dreams.”

and follows it thus, with his message:

“And every day, everywhere, our children spread their dreams beneath our feet. And we should tread softly.”