Nicotine, caffeine, alcohol, methylphenidate.

Nicotine once. Friends at the time said I needed to try it to say for a fact I didn't like it, and I didn't like it. Then I learnt there are extremely rare cases of illnesses from just one smoke, so that advice was stupid, IMO.

Caffeine was a regular as I was self-medicating with it. Nowadays, I drink mostly decaffeinated. I wish there were more flavors and variety for it, though, at least a chocolate one...

Alcohol has always been an occasional thing for me, once or twice per year. I try to keep it that way because my family has a long history of substance abuse disorder.

Methylphenidate once. I borrowed it from someone's prescription. I thought it would help me get energetic, euphoric, etc. Well, it was calming, and for the first time in my life my mind was quiet. It was so strange to be sitting with no turmoil, no direction of what to jump to do or even say spontaneously. It was just me and the silent room. Tranquility, so much that it was uncomfortable as it was new and not what I expected at all. Turns out I have hyperactivity and the medication turned it down.

If I were to say, I prefer uppers and I'm curious about substances like cocaine, but I don't want to risk my health. I'm fine.