I don't even think you should tell the audience you're improvising. It's like an apology in case it's bad : 'we're just making it up' If the improv isn't better than the rehearsed stuff, then you should just rehearse it.
Keith JohnstoneThe problem's always been to deal with the fear.Cos the fear is pretty . . . it ruins everybody really.
Keith JohnstoneAs I grew up, everything started getting grey and dull. I could still remember the amazing intensity of the world I'd lived in as a child, but I thought the dulling of perception was an inevitable consequence of age - just as a lens of the eye is bound gradually to dim. I didn't understand that clarity is in the mind.
Keith Johnstone