Hunter S. Thompson said this quote

It had been a bad trip ... fast and wild in some moments, slow and dirty in others, but on balance it looked like a bummer. On my way back to San Francisco, I tried to compose a fitting epitaph. I wanted something original, but there was no escaping the echo of Mistah Kurtz' final words from the heart of darkness: The horror! The horror! ... Exterminate all the brutes!