Final answer:
The sentence showcases the impact of intense dreams or hallucinations that seem so real that they cause substantial emotional effects on the characters.
Step-by-step explanation:
The vivid dreams and hallucinations described in the excerpts provided seem so real that they affect the characters deeply, causing fear, anxiety, and a blurring of the lines between reality and imagination. These intense experiences resonate with the reader, emphasizing the power of the mind to conjure up convincing realities. Whether it's a face of horror, an opium-induced depression, or the detailed perception of nature, these vivid experiences demonstrate the remarkable and often distressing capability of the human psyche.