Firstly, there is no such things as perfect abstractions, hence the The Law of Leaky Abstractions. Secondly, without abstraction we would be writing in machine

Firstly, there is no such things as perfect abstractions, hence the The Law of Leaky Abstractions. Secondly, without abstraction we would be writing in machine code. So unless the authors enlightens us on what makes an abstraction wrong the whole discussion is a waste of time.