One: The marijuana plant is in no way physically addicting. If you smoke weed everyday for a month and suddently get cut off, you will probably want more, but you wont be sitting in the bathtub throwing up on yourself and shaking from the cold chills. Every drug is mentally addictive, few are physcially.
Two: NOBODY has a natural immunity to any hallucinogen. You cannot "snap" out of a trip by your bodys own chems. There are drugs to end a trip short or calm yourself down yes, but in no way shape or form will you suddenly stop tripping, unless you are murdered, then its something completely different.
Three: Shrooms dont only come from cow shit, some are found growing out of rotten logs.
Four: In no way shape or form is any chemical from a hallucinogen stored in your spine. It is processed around your body a bit, does some receptor foolin in your brain, and gets metabolized into something else by your liver.
Five: If i have done said drug before, i WILL know how high, or low in the case of downers, I will get off of it. 30mg oxycodone will give me the same trip again and again until i either ingest it a different way or develop a tolerance, in which case i will just take more to get desired results, within the safe limit for my liver of course.
Six: To add to five: If your taking pharms, xanax, hydrocodone, oxycodone, etc. How the fuck do you think doctors can prescribe you stuff if they dont know how much of X drug will have X effects? Its called measuring. www.google.com
<-- use that and look up "Scale"