Personally i believe that life on earth started because of aliens and they modified life to live here, also gave us cannabinoid receptors and this fucking amazing plant they invented that can save the word in every way imaginable, food, clothes, shelter, fuel. paper, food for the mind, this plant is called Cannabis.
Our brain has cannabinoid receptors while cannabis is the only plant that produces cannabinoids meaning it has a purpose for our brain, cannabis is the only plant one earth that has separate male and female plants, this is because aliens designed it this way so you dont have to smoke weeds if you dont want to.
I think i read earlier THC was produced by the plant to protect seeds and thats idiotic, the plant produces more when there are no seeds so whats it protecting?
EDIT: and nothing can explain the psychoactive properties except being designed for human use, it has no effect when eaten, it doesnt protect it from any predator, it actually has high cellulose levels which makes animals want to eat it, this may only be the male though, im not 100% sure.
EDIT EDIT: The plant would not evolve to produce thc to please us because the plant has no connection to humans, it doesnt know how our brains works or what we desire. you cant just tell a plant to make a drug for you.