What books have you read where you thought 'this is sooo wrong' but you enjoyed anyway?

So, I read Under the Skin by Michel Faber and Perfume by Patrick Susskind and I really enjoyed them but all the time I was thinking 'this is soo weird and rather sick'. I'm looking for other books in this vein. I've heard Iain Bankses 'The Wasp Factory' is also like that but are there any more?