People really tend to underestimate the effect that cannabis can have on a trip, especially people to whom smoking weed constantly is second nature. Weed can really kick a trip up a notch, and in some cases push you over the edge. I sometimes turn down joints when tripping (much to the confusion and consternation of my friends). It's odd, though, because sometimes I'll smoke loads during a trip and not even notice it. Never mind YMMV, substances can effect the same person in different ways on different occasions. No, there's not much good coke over here, although we have kind of a two-tier market, where "Peruvian" is generally higher quality and more expensive than the run-of-the-mill 15% pure stuff (yes, really, that is average).