It all started to go downhill under the fluorescent lights of the Supermarkten in Amsterdam. I had eaten a mushroom ‘space cake’ about 45 minutes earlier. It was starting to kick in; I could feel the blossoming rush of awareness. But the setting was all wrong. I was supposed to have reached the Vondelpark (the central urban park of Amsterdam) by then. Instead, I was in checkout lane hell.

I had packed gourmet cheese and a nice bottle of red in my backpack. I just needed to get some good bread to compliment it. But it was Sunday, and learned only after I’d eaten the ‘space cake,’ that all the local…