The short answer is that I don't really know. I just haven't tried them yet.
The long answer is.....
I never made a decision to not try chemicals (this includes alcohol). At first, when I was 12 and everyone around me was getting into them, I coincidentally became very socially isolated, and missed that whole 'all my friends are doing it' period altogether. By the time I did have friends again, I had become aware that I was deeply afraid of getting high. Not for any coherent reason, just because the idea of being in an altered state terrified me on some root instinctive level. Then on top of that, I developed a sense of superiority because I hadn't tried it yet. That only lasted a few years, but it contributed. By the time I had dropped the 'I'm so cool because I've never been high' thing, I was 23, and I was completely past the part of my life where I was in constant contact with people who were using. I had gotten used to being clean, and it seemed normal. I didn't know any of the people who were into drugs or who drank much, because I was generally socially isolated (still) and also because when you don't do drugs, people who do don't like to hang out with you much. Also, my main friends were the people in the band, and NONE of us used chemicals much.
Later, two more influences came up: First, as I got into my mid-late 20's, I began to see and get to know some
casualties of drug us. There was my friend in Vienna, who died of a heroin overdose... There was my friend who
told me that she had to drink first thing in the morning to stop shaking and to avoid seizures... (she's recovered now)
there was a good friend who said her nose was still bleeding one YEAR after she stopped using cocaine by going to
treatment... One of my best friends ever talked at length about how her life was going nowhere for 18 years because she
had been an alcoholic, and that after she got sober, she completely turned her life around and started her own business...
Second, I came to understand how many people in my family tree had had problems with alcohol. I began to suspect that my susceptability to addiction would probably be high.
SO.... Am I telling you not to try drugs or drink? Not really, but I will tell you this:
1 - Don't kid yourself. Eating stuff that isn't food that messes with how your brain works is not some sort of harmless 'mind-expanding' experience. It's hacking your brain. Check this out. Maybe amplifying the signals in your brain sounds like fun, and maybe it is. But our species will never be able to go back to not knowing that those signals define who we are. Your personality is made up of the character of the flow of nuerotransmitters in your brain. If that flow changes, you change. If you manage to have interesting insights or experiences as a result, congratulations. But it's an expensive and dangerous way to have 'experiences'. And in the end, it's mostly about not being in yourself. That can become a bad habit.
2 - People who are wasted all the time don't grow. Being high turns off that subtle part of life in which we process our experiences and ideas and develope insights. Without this, you'll be 19 when your body and everyone you know are 32. That's not as cute as it sounds. Marijuana is the worst for this. Potheads tend to be losers. And pot isn't some cute harmless herbal tea. It makes you wasted. If it didn't, people wouldn't smoke it.
3 - Why is it that a culture which is hyper-suspicious about food additives, to the point where they believe that all preservatives are bad, even though they're not, has no problem at all with taking all sorts of intense chemicals into their bodies from people they barely know, which has gone through no reliable quality control, no FDA testing, with no accountability for purity, dosage, or even what the hell it is? The fact that people are willing to take those chances should tell you something.
4 - Alcohol is just as bad as any other drug. The only advantage is that since it's legal, it's less hassle.
5 - No, experimenting won't kill you.
I know that I'm a statistical anomaly. Almost everyone at least tries chemicals. Not everyone does them to the point of damaging their lives. But eveyone should know that it can happen. These things aren't safe. A lot of things in life aren't safe. My car isn't safe. But when I'm driving my car, I'm still me. And that's the real bottom line, isn't it?