Think of the dingiest, most random place you ever got drunk. Filter out the dormitory ragers, house parties, strangers’ stoops and breweries with too-high-ABV beers. I’d bet you went from “buzzed but still with it” to “We need McDonald’s immediately” in a dive bar. What does that once-derogatory term really mean? The answer is less a litmus test than a vibe check, though you can count on some constants.