Critical listening and altered states

Ok, this is not a question about relaxing, but about listening to evaluate how the system (or a piece of gear is sounding).

What, in your experience, are the pluses and minuses of altering your state of mind for listening? This can include anything you've used to affect your everyday state of mind, from coffee, beer, scotch, tobacco, to much stronger — and psychoactive, dissociative — additives.

What do you gain by altering your consciousness in terms of what you notice, attend to, linger on, etc?
What causes more details to emerge?
What allows you to stick with a thread or, alternately, make new connections?

Or perhaps you like to keep all those things *out* of your listening; if that's you, please say a bit about why.

I guess I'm reflecting my Germanic roots in that I want my system to be satisfying both when "unenhanced" and when "enhanced" with THC.  Both scenarios are equally valid for me (although I must agree that the THC mode is often quite special).  If a component or system change doesn't pass both scenarios, I don't go with it.
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THC helps me enjoy music more.  It has even helped me make important decisions in my life, including audio purchases.  I don't care if others don't use it or don't like it, but I'm grateful for having access to it and have been for many years.

Psychedelics, in their time and place, have this effect to a much greater degree, but are best used sparingly. 

Alcohol, on the other hand, not as useful in my experience. 

I'm strongly for the legalization of THC and other drugs while being strongly against their prohibition. 

To those who dislike government interference in their lives generally: what could be a greater personal freedom than deciding for oneself what to put in one's body and mind?