Creativity is not outside the box!

I must admit that I'm still having trouble with this: people keep saying that you should think out of the box if you want to be creative but ever since I heard the following I've been seriously disturbed by that notion:

List as many things as you can think of that are white, write them all down for 1 minute, maybe 2.

Now think of all the white things in a fridge, and write them down.

Which was easier?

You with me????

To be creative, it seems to me that you need a box to think within. It's much harder to just dream up anything. The definition of creativity, or of new ideas, is when you take two (or more) known things and combine them in new ways. Same thing - start with something that's known. So what's this box, that everyone wants to think outside of?