People also react very differently to smoking the plant.
An important aspect imo.
Now I smoke 0.4g/day (from 7 joints in 7 hours) but have smoked 1.0g/day in the time that I studied physics and taught mathematics (calculus etc). I have had no hang-overs and my preparation meant that I could teach without too much thinking. I never have had headaches from alcohol no matter the amount I'd drunk. The last time I was drunk is >2 years ago.
I have worked with people who were smoking potent stuff all day and didn't seem that affected. I would become lethargic I think.
I used to smoke sativa (amnesia haze) but, probably because of other ingredients, I kept getting small bloody pieces of arteries from my nose in my handkerchief (from runny nose). Alarmed by that, I quit with sativa and have only smoked low-thc indica (white widow) since. Alas these days almost all marihuana you buy is a hybrid and they keep getting stronger in THC-content.
Off-topic (sorry kassy, perhaps move the thread?):
I have ordered 4 quality seeds online from 2 varieties which I pick up this afternoon. One goes in a pot on my balcony and three are to be planted in my community vegetable garden. That's the plan.
Having my own harvest of the stuff would mean an enormous budget relaxation for me i.e. it would increase my 'disposable income' by a factor of 5 or more. And a further big advantage will be to know how it's grown; without pesticides and other chemicals and outside in the soil.
Personal update: I don't drink alcohol at home anymore and I drink less. And I smoke less. This is a multi-year trend. I have no partner or children or other family to make me do it and I am in very good health and I don't care what others think of my usage so this is just from my own discipline and path. Even though I have no future and no friends and a low status. It is great to have strong disciplines without enforcement from groups, cultural, health or other. I really love to eat chocolate but stopped with that too. Just as with coffee and milk.
I think am less addicted to marihuana then most others are to their car and lifestyle. If I am addicted at all.
After a couple of joints my eye whites will be a bit rose/reddish and my face a bit different and other people then may think that I am under influence and not clear thinking anymore, but that's not the case at all. My thinking works like a dream then. Often I have made ASIF posts after 8 joints and 1.5L of lager beer. Almost all my research in hermitage is done in a 'stoned' or 'high' state (more outliers and outlier-patterns show up, it has a function!). Most of the time I get 'high' from smoking because I have a lot of energy and motivation. I write ideas in my agenda and past years agenda's are all written full of text. They are still valid and correct the next day, might you wonder. A matter of calibration and scientific quality of thinking.
