I have to say, thinking inside the box is indeed underrated; it's my opinion that the 'box', as it were, should just be ignored, because thoughts within 'the box' can be just as deep as those without. Just as much insight can be gained from looking very deeply into previous thoughts, possibly coming up with 'new thoughts' in the process, than trying to be different and taking up a position contrary to the conventional. Indeed, I think that to an extent, rebellion (of a particular, predefined kind) is actually now encouraged by the media so much that it is paradoxically a form of conformism. As I say, I find it's best just to ignore the idea of a box at all, and measure your thoughts by your own standards, your own intellectual compass, regardless of whether it's unconventional or not.
Sorry to go on this huge tangent in a disucssion about T-shirts; I'm in a verbose mood.