Is it possible for something to be too delicious? Do we avoid certain culinary creations simply because we know that if we ever tried them, everything else would pale by comparison and normal life would feel empty? Because there must be some reason why boozy milkshakes aren’t more common.

Millennial-hipster culture is essentially an endless joust between juvenile nostalgia and faux-sophistication. The result is that no one matures to actual adulthood anymore; instead, one can choose to play act as a grownup when the occasion requires yet cling to childish things the rest of the time. The signature millennial skill is the ability to fuse these attributes into unified adult/kid mash-ups: academic symposiums about superhero costumes; high-salary jobs designing balloon-popping apps; and, now, super-sweet milkshakes spiked with enough vodka to flatten an elephant.

It’s not as if no one has ever thought of alcoholic milkshakes before. The Hideaway — which opened in February as the successor to Bourbon & Beef — has decided to take the plunge and feature milkshake cocktails on its menu.

“We’re a gourmet burger joint, so we’ve gotta have milkshakes — but we also have a full bar, so we’ve gotta have cocktails, too,” manager Katherine Schiele said while busily serving customers during a lunchtime rush at the Rockridge restaurant.

“So, it occurred to me: Why not combine the concepts? Why not feature milkshakes that satisfy the craving for cocktails? Or cocktails that are actually milkshakes?”

But creating a memorable shaketail menu isn’t as simple as blindly upending the nearest bottle of liquor into any ol’ milkshake.

“Not everything goes well with ice cream,” Schiele explained. “I wanted to have a shake for every type of spirit — bourbon, tequila, vodka, and so on — so I had to consider: What’s the best flavor profile for each liquor that would still go great with ice cream?”

The Hideaway’s geographically themed boozy shake selection includes two recipes which Schiele called crowd favorites: the shamelessly hedonistic Pacific Northwest, thick and creamy and heavily infused with coffee liqueur, chocolate syrup, and vodka; and the East Coast, incorporating bourbon and maraschino cherries and which “tastes like a Manhattan cocktail, in milkshake form,” said Shiele.

She also recommends the South of the Border: Featuring tequila and lime, it’s reminiscent of a Key lime pie smoothie. The piña-colada-esque Caribbean Happiness (rum and pineapple) and North Pole (peppermint schnapps) complete the boozy shake menu — for now, at least.