I do not expect you to understand what is written below. But i prefer to make my point.
Although i prefer other sources as well, i will stick to wikipedia this time.
http://en.wikipedia.org/wiki/Nicotine
http://en.wikipedia.org/wiki/Cocaine#Physical_mechanisms
You are right about LSD, which i never mentioned as addictive. But it is mind altering and can be a psychosis trigger in other wise normal people. Not a good idea to have people who have to work high on LSD though, keep it illigal.
It is too heavy.
http://en.wikipedia.org/wiki/Lysergic_acid_diethylamide#Adverse_Drug_Interactions
MDMA or ecstacy, is not addictive but if you have bad luck or have been using for years , you have a changed brain chemistry for life. And that does not mean you turn into a scanner or your children are scanners.
http://en.wikipedia.org/wiki/MDMA
One person have been seen to benefit from MDMA. This person has parkinson. There is even a documentary made about him.
http://news.bbc.co.uk/2/hi/health/1169980.stm
Cannabis is not addictive for most people. But people who have a genetic fluke might find it more difficult to stop. Especially after daily using for years. This is reality and not something i make up. Using every day does change the parts of the brain involved in memory processing. Using once in a while will not be an issue. What you forget is that you should ask yourself why you should put chemicals in your body to make you feel good. You should ask yourself that.
If you want an "easy" way to feel euforia , i will give you a hint of what you should master :
Lay down on your bed without taking any form of substance besides healthy food.Try visualizing in your mind yourself in your room with as much detail of your as you can. When you can do this you wil feel a sensation of pleasure.
When you have done this, try visualizing the planet with as much detail as you can. Try to see yourself in your mind laying on your bed while trying to keep the proper dimensions of the earth and keeping the planet earth as well in your head. When you can do that while keeping proper dimensions, you will not desire for drugs. When you can do that, and you have enough rest...
You will be able to do lucid dreaming. Imagine being able to do everything you see in the movies while in your dream because you know you are dreaming. When you can do that, perhaps you will find that drugs are useless. It can only be done when your brain functions properly...
http://en.wikipedia.org/wiki/Lucid_dream