"I don't consider marijuana part of this since I don't consider it bad"
MORALISM ALERT!!!!
surely you know that "legal" (to some, therefore not "bad") drugs cause far more death, bad health and unhappiness than all illegal drugs. those legal drugs include: alcohol, tobacco, coffee, sugar, prescription meds, etc.... what exactly makes one drug "bad" and another not? its health effects? its behavioral effects? in an anarchist "society", would you choose to tell others what they can and cannot put into their bodies? or even what is "good" or "bad" for them?
i know *many* functioning addicts. why would being an "addict" even be considered a problem, if the addict is not impacting others as a result? is nicotine addiction considered "substance abuse"?
perhaps i misunderstand the question, or its framing.
i guess the real crux of this question is (hyper generalized and boiled down to anarchy101): "but who will take out the garbage?".
individuals, solely and in concert when desired, would assumedly deal with undesirable behavior (or situations) in whatever ways they choose to. there is no single answer, since that would imply a fixed, rigid system - not unlike what exists today. the context of each situation would hopefully influence the actions taken by those involved.
being somewhat proactive with people you care about seems like a good idea for meaningful relationships. but in general, why would you give a shit what anyone else wears, eats, drinks, smokes, fucks, sings, etc... unless it impacts you directly. geez, i thought all the vegan vs non-vegan, straightedge vs non-straightedge, scenester stupidity got dumped in the early 2000s. moralism gets 86'ed.