If you are referring to illegal drugs (leaving the listing as 'drugs' is too wide a category) than I must answer in a word- experimentation. People like to experiment and push their limits and drugs (for all their dangers and side effects) work. . .I could tell you that I regret all of my experiences in high school and college- but I don't. I could tell you that I wouldn't do it again- but I won't. I don't do it now because I find the prospect boring- "why live in the past? Do something different". . .I'm at a different place in my life with family and responsibilities, but all the experiences that got me here (good and bad) are part of my personal growth. . .I wouldn't recommend my life to anyone- but I won't pretend it wasn't a kick-ass time. . .