this is what I posted on the Carl Sagan thread last night (the 2nd paragraph of my post being the relevant one here):-
I can relate to the start of his second paragraph, which was my experience (one of my girlfriends was a big-time pot head) and I never took things any further; it has never done anything for me THC and I look to get my kicks in other ways.
since I also have connections and worked in the pharmaceuticals industry (at the research end) I wouldn't ever go near LSD. Unlike some stuff, this invidious compound can actually react with your brain and cause chemical changes inside of it. Now I don't know enough about this to understand if that is what causes people to have LSD flashbacks, but I'd just as well steer clear of it irrespective.
City is of course my drug (and religion for that matter) of choice...