Almost 20 years after my Mamma Mia!-assisted sleep therapy, I’ve learned not everyone can replay scenes – real or imagined – in such vivid detail. It is a nearly impossible task to objectively describe how one thinks, and how our unique way of thinking may be different to others. But my ability to picture the exact blue of the sea and recite the line delivery was, to me, always clear – and it has a name: hyperphantasia.