Obviously, we consume foods and beverages for a number of reasons, one of which is because we like the flavors of them. So if you like the taste of PSLs, and can tolerate the ingredients, then you should go for it. But if you're one of those people who knows that one or all of these ingredients — sugar, lactose, coffee, or carrageenan — can cause your stomach rumble, you might want to think twice, or at least have easy access to a bathroom, before ordering your next PSL.