Alcohol is weird. More so than any other food, if we can even call it food, alcohol compels us to indulge in unusual flavors. It's all bizarre stuff if you really think about it. Whiskey is nothing but used wood solvent. Rum is diluted molasses that has gone bad. Beer is spoiled grain augmented by the flatulence of microscopic fungi. More to the point, ethanol is poison. Our bodies treat it like a toxin and it inhibits neural function. The fact that we consume the stuff on purpose, for fun, is beyond absurd. Maybe that's why we're willing to drink alcohol with weird or downright off-putting flavors. We're already consuming something wretched and strange, so why not take advantage of the requisite state of mind and experience other odd things at the same time? This is where the acquired tastes of alcohol begin.
When it comes to the definition of "acquired taste" in the realm of potables, I have to set the bar a bit higher than most. Scotch, for instance, is often called an acquired taste. This is ridiculous. Acquired tastes are not based on the sole criterion that there exist people in this world who don't like a particular flavor. By that metric, chocolate is an acquired taste. Scotch certainly has a challenging flavor, but there are such a wide variety of different scotches and such a layered profile in the middle-of-the-road batches that there's no way to even describe the way "scotch" as a concept tastes.
That in mind, there are some specific scotches that are decidedly acquired tastes. Consider Laphroaig, an Islay scotch that has been gaining popularity lately thanks to its idiosyncratic taste. The stuff tastes like a campfire. There's no better way to describe it. Its flavor is functionally identical to the scent of smoke off a pile of burning wood with no accelerants to aid the flame. Even for card-carrying scotch drinkers, Laphroaig is damn near unapproachable. A lot of good bars keep the stuff on hand to make unusual cocktails, using it like the mixology equivalent of liquid smoke.
And yet there are people out there who are in Heaven when they can get their hands on a deep glass of Laphroaig straight-up. Maybe it's connected to a sense memory for them, maybe it just tickles a particular synapse in their unique brains. Most probably don't even know why they've acquired the taste for campfire scotch, just that they like it while the majority of other people wouldn't even identify the flavor as palatable.
My personal acquired taste is Fernet Branca. It's part of a class of liquors that haven't been in fashion for nearly a century and even then were mostly used as after-dinner digestive aids in continental Europe. Only the sweetest and simplest digestivi survived into modern bartending, like Sambuca and Grand Marnier. Fernet Branca has only just come back into the American cocktail palate, and with good reason. On its own the stuff is incredibly bitter and has a pervasive, antiseptic mint note. Sipping it is a terrible idea. Either take it all at once or mix it with something. It's been popular in Argentina for a long time to mix Fernet Branca with cola, which is my preferred way to drink it. Maybe I like it because I have a high tolerance for mint, or maybe I like it because it reminds me of the smell of a fancy spa shampoo I loved in my teen years. All I know is that most people can barely stand the drink and I wish I had a bottle of it wherever I go.