Meh cannabis is complicated for me; it can get me quite anxious and paranoid sometimes; obsessive and negative thoughts (more emotions though) can trigger (a focus on Fi); like a key to the lock of an imaginary box with negative emotions, very unpleasant. Sometimes I really think I should quit, or at-least quit in social situations, I generally hate smoking with people unless I'm extremely comfortable with them, because paranoia/anxiety can be a bitch, I cannot utter or form any comprehensible sentences. I realized though, if I smoke really small quantities, I cope way better, both alone and in social circumstances; I make the effort not to smoke myself stupid, stoners seem to love doing that. On the other hand...
...Sometimes it's the complete opposite, almost always when I'm alone, my mind feels amazingly clear, I'm aware and greatly in tune with both my body and senses, my Ti diminishes, I feel pure, raw, alive, and instinctive, and the thoughts I do have are extremely concise, objective, and my Drug induced Ni compliments these thoughts perfectly, I reach conclusions, putting me at complete inner peace, of what feels to me like a perfectly balanced psychological equilibrium; driven away from the fear of ignorance... A very blissful state (I've achieved a similar state on shrooms, although I'm thinking that the first time I achieved such a state was on shrooms... Hmm). My imagination becomes very vivid and under my control, particularly when I'm falling asleep, the mental images I form are so subjectively great, I've sometimes noted details of them down when I could to consider tattooing them.
...Then I fucking wake up.
But essentially, in my case, it's the minds choice based on numerous factors I cannot comprehend, to which buzz I'm on, shame I don't have control.