Where do I start and stop, is what I want to know.
Obsessions often feel like the work of some cruel and sentient force equipped with its own devious logic, showering you with the exact thoughts and images you find most disturbing and devising new monstrosities as you defuse the old ones. Obsession knows you better than you know yourself. It outwits you. For this reason and others, insight is slippery even for diagnosticians. How is it defined, and how much of it is a patient supposed to have? Are lapses in insight allowed? What sort? How many?