Food for Thought
"According to Madam Pomfrey, thoughts could leave deeper scars than almost anything else.”
Ron needed special treatment after being touched by the tentacles of a brain in the Department of Mysteries.
This sentiment echoes a statement from Masekhet Yoma 29b, הרהורי עבירה קשים מעבירה, which claims that thoughts of sin are in some way more serious than the actual act of sinning. It is not enough to avoid the actual sin--one must be concerned with the spiritual damage that can be caused by the (obssessive?) thoughts of sin. Why do you think this might be? This is a statement which, if misunderstood, can lead to unhealthy attitudes of inadequacy on the part of people struggling with their self control.
Here is one collection of explanations of the idea, from the Kipa site.
What do you think a healthy attitude towards such thoughts should be?