I was what you'd describe as a stereotypical "stoner" all through high school. . . where I never was able to find or use marijuana, because I was in a very religious community in a very rural area. If anything took any amount of effort, I'd quit, I had no motivation to achieve my potential, my sole motivation was to slip by with as little effort as possible i.e. refuse to turn in homework then ace the tests and challenge the teacher about giving other kids "A"s who's knowledge of the subject matter in now way exceeded my own, because of "busy work" designed to reinforce the topics which was obviously unnecessary since I could ace tests on the subject all day after learning it one time from reading it. If there was high input tasks like research papers or term papers, I'd cheat my way through those. This worked fine up until college calculus 2, and engineering math classes where there's only 5 questions on a test and getting one wrong meant an instant C on a test, and I failed classes, lost my college scholarship, and decided I'd finish out the classes I was passing, then drop out (cuz I was a quitter) and pursue playing guitar to become a professional musician. I asked my bandmates if they could find me acid, and they were like "whoah you trip on acid?" and I told them "no, but I want to get more creative and more into writing", so they suggested marijuana, to which I went on a right-wing rural area religious indoctrinated kid tirade about how it was just "stupid" for people to purposefully inhale smoke (says the guy just asking about acid) and pot makes you lazy, stupid, stinky, etc. They pointed out the errors of my logic, and talked me into trying it which I did, and I liked it very much, there was euphoria, but not a loss of identity or control or knowledge that I'm still just a normal me who feels better, not a stupid me who feels good but is now less intelligent. I asked for some more and went home with the purpose of using it and writing songs. I never got to my guitar, because I smoked out outside, then needed to clear my table and area of my school books. . . which I picked up and started reading with an enthusiasm and zeal I'd never had even leaving home for college to pursue my engineering degree. I loved it, and just kept reading, and felt compelled that it would be FUN to do the homework RIGHT NOW. So I did the homework for the next 3 weeks, for four subjects, cleaned my room, cleaned the kitchen, cleaned the bathroom, and organized my schoolwork and calendar. I used pot ALL DAY EVERY DAY after that, earned 4.0s in every class, earned my scholarship back and graduated with my BSEE degree. I didn't lose the ability to just be exposed to the material once and absorb it immediately. I just gained the ability to not want to leave campus until I'd also done all the "busy work" required. Just smoke out in my car in the parking lot.
Something about marijuana toggles my motivation to SUPER ON. I can't "get high and watch a movie". I feel my life wasting away as I SIT. I think of all the things I could be accomplishing and just have to DO one. On marijuana I can completely identify with the mindset of a "workaholic". I just keep adding on, like "I could also do this, and this, and this, and this." It makes scrubbing bathrooms fun and interesting, and gets you easily over the barrier of "we've got to do this horrid job, and lets get started NOW".
Before pot, it didn't seem like the dopamine reward circuitry was WORKING, I'd do homework for a class I already understand, and turn it in, get a 100% and think "See that's what I said, I don't need to do this junk", there was never a positive feeling of accomplishment like there was in spades doing homework when medicated. Its like my mind now knows if I do these tasks and accomplish them I'll get a "bonus buzz" so I'm like a rat at the switch trying to push it over and over.