Something's up when someone you've only known since March asks that question.
The answer being, any time I can't trust a bartender to make my signature Tom Collins/splash of cran right, and they don't have any cider available as backup.
You just know it's not worth it when you're in a dive bar and you see that blank look when you ask for this old man's drink, that look of, hang on, I have to look up this cocktail before I make it for you.
And, if it's not a wine place (dive bars usually aren't, but also wine's actually my last resort), then beer's your best bet.
But you know what? Sometimes? You just need a beer.
And then? Sometimes? You just need a professional Twitter account the morning after.