“Beware of these plants.” my grandfather said. “Their persistence can drive a man to go mad. I’ve seen whole buildings crumble in a week.”
“Then why do you keep them around?” I asked.
“Because I had to learn the difference between persistence and madness.” he replied. I turned away from him and rolled my eyes.
“Well don’t you feel like you’ve figured that out?”
“Yes, that’s  why I let them go.”