It is impossible to manufacture or imitate love. No, this will simply cause a powerful infatuation or obsession. It is probably the most dangerous and powerful potion in this room — oh yes,’ he said, nodding gravely at Malfoy and Nott, both of whom were smirking sceptically. ‘When you have seen as much of life as I have, you will not underestimate the power of obsessive love...’ Professor Slughorn – Harry Potter and the Half-Blood Prince
