"My dear sir, it haunted me for the rest of my life"

In this quote, Peter O'Toole is expressing a deep and lasting effect that something had on him. The use of the word "haunted" suggests that the experience or memory was unsettling and continued to stick around in his mind. The fact that he says it will stay with him "for the rest of my life" stresses the intensity of the haunting. It indicates that this occasion or thought will never really leave him and will always be a part of him. This quote communicates a sense of deep feeling and perhaps regret, as if O'Toole is haunted by something he wishes he could forget.