Because usually the "euphoria" people feel is their biology failing due to mild poisoning. It is why most people will often upchuck within a few minutes of ingestion.

People may think they are finding enlightenment, but are no different from the local deranged squirrels aggressively howling at passerby after nibbling Amanita in the fall. Apparently the squirrels use the mushroom to help preserve food stores, and it doesn't poison them as severely (often fatal for humans.)

Paul Stamets is a weird dude, but his work contains some profoundly detailed observations.

People need to think about Fungi as closer to animals that don't move on their own, and acknowledge they rapidly adapt genetically to survive. Pretty to photograph, but often far more complex than people like to admit. =3