person 1: i feel more open-minded & loose; it 'took the edge off' and helped me relax.

person 2: i feel scattered & unable to focus, like somebody put my brain through a blender, and dropped me 40 iq points in the process.

in fact, these people are describing the same thing, it's just a question of whether they're enjoying it or not.

i like marijuana at concerts.

i don't like marijuana when i'm reading or studying.