Fountainhead, Ayn Rand, page 261 of Centennial Edition -

Keating to Roark:
“It’s a secret, Howard. A rare one. I’ll give it to you free of charge with my compliments: always be what people want you to be. Then you’ve got them where you want them. I’m giving it free because you’ll never make use of it. You’ll never know how. You’re brilliant in some respects, Howard, I’ve always said that — and terribly stupid in others.”

Terrible advice.