Actually, tobacco gives me a WAY more powerfull high (I don't smoke, normally), sometimes so intense I can't stand up. Only lasts for about 4-5 minutes though.

On another note, I've done magic mushrooms 5 times and they didn't trip me out half as hard as when I was new to weed. I remember my second time smoking (the first was an incomprehensible blur) I was sitting there with my eyes closed falling down complex pattersn of colours. Then somebody threw some Megadeth on and I sat there saying "megadeth, megadeth, megadeth" just to focus my mind on something to hold it together. Finally I realized that I was standing (when I thought I was sitting) saying it and people were saying "man, I want whatever that guy's having!", and a fell down laughing unable to respond.

hell of a placebo effect