I have found that my musical "judgement" is at its most accurate when listening late at night in the dark with just a hint of THC running through my brain and ears, Got my medical card last year. What the THC does is amplify focus and eliminate "monkey mind" or rather replace it with a more delightful monkey mind perhaps. Any stress or seriousness accumulated during the day is subsumed by the high and taken to oblivion for awhile. There is also the cannabis PRAT that lets one see the music more as a totality rather than a complex of independent parts that need monitoring and constant audiophile "assessment." It takes away the uptightness that can gather around our systems as we obsess over minutiae. It gives us the excuse to be a little reckless and forgiving in our hearing without the feeling that someone judgemental is always looking over our shoulder. It makes music more of a "surprise" probably because the THC has slightly retarded our analytical thinking and memory.
That’s why Satchmo could never play his horn right without it.