I've had those 'what were we talking about' moments for probably my whole life, with or without benefit of alcohol or drugs. It happens to some of us non-linear thinkers, whom other people know as "scattered". It even happened yesterday, and I figured out what the connector was an hour later, too bad.
On California and marijuana, this is already a sparklingly well developed industry (need I mention the Dr. Kush article in the New Yorker again?). I'm all for legalization, et al.
However, I do read in my old most interesting local newspaper, the North Coast Journal, a Humboldt County paper (no immediate citation but from a fairly recent issue) that local folks are irate about new scary thuggish types moving on in, or up, as the case may be.
I'm not a smoker, haven't for many years, but I retain the rights of others on that, and for myself, the possibilities of some future brownies, whatever.
I'm not as sanguine about all drugs, but on this one I'm, er, relaxed.