I don't think the word 'no' kills creativity necessarily. But words like 'should' or (my pet peeve) 'conform' certainly kills it.

As in "I paid good money to see this band, and they should have played (fill in blank)."

or

"The academy can't teach creativity, but we can teach technique..."

followed by

"A (BFA/MFA/PhD) and a masters in education is required to teach art. To kindergartners."