I haven’t had THIS exact experience, but I know the feeling of waiting behind someone taking forever for stupid reasons, especially in Taiwan. Usually some idiot at Starbucks trying to find a QR code on their phone to qualify for a measly 10 NTD discount. Gotta wait for them to shuffle through their phone for 2-3 minutes while the barista just stands there like a vaguely smiling statue.
And before anyone says “that’s what you get for going to Starbucks”, I’ve noticed this behavior at other places too.