What is the most resilient parasite? Bacteria? A virus? An intestinal worm? An idea. Resilient... highly contagious. Once an idea has taken hold of the brain it's almost impossible to eradicate. An idea that is fully formed - fully understood - that sticks; right in there somewhere.
《Fight Club》
Taylor: The thing you own at the end they'll own you.
Jack: Self improvement is the modern masturbation.
Taylor: Who you want to fight if you have a chance?
Jack: Gandhi.