This is lovely and more than a tad bittersweet. For all the humour behind this, it also displays a fundamental aspect of the Doctor: he is an alien and in trying to "suit" him, his companions could lose more than they can imagine - they'd never know indeed. I loved Amy's attitude towards Rory here, tender but dismissive, a little oblivious to what Rory is trying to say, always the Doctor's friend. Rory is sharpest. Really nice piece!