Let me make my opinion a little clearer. I am against generally using any substance as a drug. We should be happy with the way we are. But man is often seeking new experiences, and pot is an experience which is not as damaging as others, and it provides some with a state of mind conducive to creativity (such as music, song, art, and software engineering). When I was in college (one of the top ten Computer Science schools) almost everyone smoked (and this was in the 1980s)... My best friend in High School went to Cornell University and got a PHD and now works for DARPA and he too smoked pot (and tried LSD too). I have many examples of software engineers who work for major corporations who have smoked also...
So while I think that we should not need these substances, and we should truly understand the damage caused (if there is damage caused), we should also consider the benefits. I do believe there is medicinal uses for pot, and it does alleviate pain and anxiety. It works very effectively, more than any pharmaceutical substance.
I realize I am in the minority here. But I believe my experience is not unique. And I hope that we can deal with the question in a mature way which is the best for society.