The speaker is talking to alcohol as if it were an old friend, and telling it to be quiet. The opening lines sound apologetic but firm, like someone ending a friendship they feel guilty about. The middle of the poem looks back at drinking days: whiskey, bourbon and vodka, a plastic bag of bottles, and cheap rum in the forest. Those memories are fond and a little boastful, "top of the pops," yet the speaker admits they felt "dreadful" at the time.
The repeated question "How did things get so good" is the heart of the poem. The answer is that the past only looks good because it is gone, and that life improved because the speaker silenced the drink. The mood is wry, tired and cautiously hopeful. The final lines accept that liquor can't heal anything, and the speaker hopes to recover by becoming more awake and aware, which is a playful twist on "getting woke."