I had a bad experience very recently with hash (in the non-CS sense.) There was a harm done, for a couple of hours, to my understanding of time, of recalling "when" each memory I was using was formed. I could not tell AT ALL if it was from literally 10 seconds ago, or weeks/months ago. It was incapacitating, but upon reflection, really showed as is often the case with medical science and pathology, there was a faculty at play here that was only apparent when removed. I could not function without the ability to sequence events, including the provenence of each damn propositions I was trying to use to explain my current existence. Bad times. But with some distance quite interesting.