If we look at some the greatest musicians who have ever lived we can see a common pattern involving the use of intoxicants and assorted narcotics. The list is endless.....Hendrix, Janis Joplin, Jim Morrison, Kurt Cobain, Freddie Mercury, Michael Hutchence, James Hetfield, John Lennon, Keith Richards, Jimmy Page and Ozzy Osbourne among others.
These are the same people who were icons during their time. I mean everyone knows that Hendrix was and will always be 'The Guitar God' (inspite of Slash,Petrucci and other contenders to the throne)
'Green day' is a band name but it also implies in California slang "Lazying around and smoking pot all day". What makes a musician indulge in narcotics is the whole issue. Yes, it does 'elevate' someone to a 'mind numbing' place. But the price that is paid is huge. I have had friends with whom I used to hangout and discuss heavy metal and the deepest ideologies behind lyrics, but soon with the usage of marijuana those same guys later moved onto Trance instead of Rock and Metal. This pretty much put them out of the group's hangouts as well as on various topics of discussion.
When we listen to Floyd or a even Dream Theater this is exactly what we try to achieve, a higher state. Yes the feeling that someone would get after smoking a joint and listening to "Coming back to Life" would probably even be better than anything else before that. (Some other guys I know would probably prefer Tool over here instead of Floyd)
Some of the most famous pieces of music were probably created when the band playing it themselves weren't aware of the notes being hammered out. Metallica themselves say that the "Kill em All" tour is something that they hardly remember anything of since they were mostly stoned while on stage. (Ref. the Live Shit - San Diego DVD)
Now if anyone thinks that all the substance abuse ended with Kurt Cobain needs to think again. Recently multiple Grammy winner, Amy Winehouse had some issues on that front.
There are choices to be made (maybe life altering one's) faced by most of us. The idea trying to be conveyed here is quite similar to the film 'Thank You For Smoking'