It's not the wine that intoxicates people, but people who intoxicate themselves; implying that one's feelings or state of mind are often determined by one's own predisposition rather than external factors.
他常常沉浸在自己的幻想中，仿佛“酒不醉人人自醉”，完全活在自己的世界里。
He often indulged in his own fantasies, as if 'wine does not make one drunk, but one makes oneself drunk,' living entirely in his own world.
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