You can have whatever you want sounds far too good to be true, the world just does not operate that way. Does it?
In her book, The Secret, author Rhonda Byme says yes it does, under certain circumstances. With a very different twist, author Annemarie Postma in her book, The Deeper Secret, puts it thus: The Universe ..gives what you require, but not always what you think you need.
The technique is similar in many respects to the one described by Barbara Mohr in the now well-known book called The Cosmic Ordering Service.
Based on the Author's experience, early in the book Rhiannon instructs Geraint on a technique to provide just that - anything that he might want.
Of course there is a catch to it. It is is a very simple issue you have to overcome. You have to believe completely that you deserve what you ask for. You then make it come true, by visualising it clearly and powerfully. This is the technique that Rhiannon describes, and having done this, you let it go, knowing that you will receive what you have asked for, although it may not be immediate.
How does it work? I don't know, all that I know is that somehow you get what you need, which is not always the same as what you may want.