I like the two quotes Lisa Nichols from "The Secret" r(ecently featured on the Oprah Show) frequently uses.  One of them is something like, "when you're thinking about something it's like you're placing an order to the universe" and the other one is, "the universe doesn't hear that you don't want it".  Although she doesn't go into details, this is how I understand her two quotes.

We are all in the unusual restaurant called 'the universe' where everyone and everything is both a customer and a server all at once, since everthing shares one energy, there are no separate entities.  This restaurant has an infinite menu that you can order from and when you're ready to order, all you have to do is focus your thoughts on what you want.  Someone in the restaurant (it might be someone you know, a stranger, or even yourself) will bring you your order when it is ready. 

On the other hand, if you happen to be looking at the infinite menu and thinking only about what you don't want, your server will bring you exactly that which you do not want!  That is because your server not only did not hear you say you didn't want it (why would anyone only tell their waiter the thing they didn't want - it's usually assumed in restaurants that when you name something from the menu, that's the thing you want?) but you didn't choose a single thing you did want from that infinite menu!  If you don't want a specific thing, you must choose something you do want - you aren't stuck with it forever - you can choose something you want more afterwards.

So as they say in "The Secret," you use the Law of Attraction whether you want something or don't want something - you get the thing you're thinking about most.