Seldon shook his head. “It strikes me that no one could possibly want to be Emperor.”

“No sane person would, I agree, but the ‘Imperial wish,’ as it is frequently called, is like a disease that, when caught, drives out sanity. And the closer you get to high office, the more likely you are to catch the disease. With each ensuing promotion –“

Issac Asimov, Prelude to Foundation

The context of the above quote is a conversation between the characters Hari Seldon and Dors Venabili in ‘Prelude to Foundation’.