Listen To The Mustn'ts

"Listen to the MUSTN'TS child,
Listen to the DON'TS,
Listen to the SHOULDN'TS,
The IMPOSSIBLES, the WON'TS.
Listen to the NEVER HAVES
Then listen close to me-
Anything can happen, child,
ANYTHING can be."

Shel Silverstein, Where the Sidewalk Ends