Agreed.
If you aren't responsible enough to know when you may be taking things too far (AKA said examples Crono has listed), you must be pretty naive.

________

I don't consider weed a drug. It's a great thing for exploring oneself.
It's very hard to explain, but you just notice things about yourself you haven't before.
I learned that my roomate is much more assertive and ends conversations quicker than I do. I've learned that, at the time, I would always say "Just kidding" after everything I joked about (a lot), and learned to stop.
I also noticed I talk higher pitched than my roomate, and though I can do nothing about it; it's just an example of the small details you notice.

It's also pretty cool for imagination. I've had tons of ideas for writing books and programming games. Especially while listening to music, I always imagine darkness fighting the light (and vice-versa). Per musical tone change determines who is winning, the darkness or the light (sounds weird, but it's absolutely amazing).
Sometimes you get so drawn into these things, you make up an entire story in your mind and believe it's all true, until a simple interruption (I.E bang on the wall or door closes) snaps you back to reality.
It has given me so many ideas I'd like to interpret into Graal3D, as well as mentioned above: making a book. Even writing songs would be great.

Sorry for the long post, but if you're so against something truly unique and an exciting experience, you're definitely missing out.
Not bad for you > Entertainment > Increases productivity > Explores the mind.
You'd be crazy to deny such fun.