Staff at the global coffeehouse chain spend most days making the same old drinks, which they've whipped together so many times they can practically make 'em with their eyes closed.
But every now and again, a customer comes in and requests something a bit left-field which takes them aback.
One such barista - who goes by the TikTok handle @kenmixtape - decided he had to share the 'grossest' drink order he'd ever received with the world.
In a video viewed more than 2.1 million times, Ken showed himself concocting the unusual tipple.
First of all, Ken mixed together the chain's mango dragonfruit beverage with some lemonade.
So far, so refreshing. But then came the unorthodox twist that upset Ken.
The customer asked for a shot of espresso to be added into the mix - which Ken labelled 'so disgusting seriously'.
Taking to the comments, many people agreed with the barista.
One person wrote: "... It was fine until the espresso was added like why."
Another added: "That's absolutely rancid."
A third said: "Did... did someone lose a bet?"
However, others said the cocktail was nothing unusual in different cultures.
One person wrote: "Lemonade and cold brew (maxagran) is a common drink in some parts of the world so this doesn't sound that strange lol."
Another said: "Here in Portugal there is a drink that is freshly made lemonade with an espresso mixed in ice so I'm sure I'm fully weirded out lmao."
A third added: "But citrus and coffee are paired together so it's not all that strange."
I suppose it's just a matter of taste, then. What we know for sure though is that the drink wasn't to Ken's taste. In a follow-up video he tried it himself and was not impressed at all.
As long as the customer liked it, I guess that's all that matters.
However, some Starbucks workers are getting sick of ridiculous customised orders, which they attribute to platforms such as TikTok.
Workers told The Guardian that viral videos on 'secret menu hacks' and personalised recipes are increasing the demand for complex orders.
A shift supervisor said: "These orders are driving us insane because they're so long, so specific and it requires you to do much more work than you should be doing for one single drink and they're not being adequately translated into our labour hours."
An anonymous Maryland barista added: "With mobile order or delivery, we can't always clarify what they want and people will get very mad over sort of little stuff when you've made the drink almost perfectly, and it's frustrating to feel like you can't say we can't really make it that way, so people treat us like coffee-making robots."Featured Image Credit: PA