Boxes are restrictive, maybe you're afraid of what you interpret as limitations?
It means whatever it means to you.
If the box is a recurring theme, just get yourself into the habit of thinking "Oh, a box, am I dreaming?" each time you see one, then attempting to will it out of existence.
it means too much yume nikki
You do realize that whenever he/she goes to a shipping company that they're going to pull an inception and never believe they aren't dreaming now.