Because it is enjoyable

Reason's Hit and Run blog has some highlights from a cover page article in the New Scientist which answers the question of why we choose to alter our consciousness by injecting chemicals.

Pleasure, excitement, therapy, novelty: seen in this light, the pursuit of intoxication looks very different from its standard portrayal as a pathological drive that must be suppressed before it leads to harm, addiction, and squalor. Yet the mainstream debate on drugs, alcohol, and tobacco seems unable to acknowledge that there is anything positive at all to say about intoxication. Instead it is locked into a sterile argument between prohibitionists and those who want to reduce the harmful effects by, for example, making heroin available on prescription. Both groups start from the belief that psychoactive substances are inherently harmful but disagree on what to do about it.

I'll need to try and get my hands on the full article. It may introduce some new ideas and concepts into the drug debate, many of which I can deploy in discussions against my 'drugs are evil' friends.