Ordinarily, I enjoy going to Starbucks. but on one recent occasion, the barista made my drink and then noticed that I was a "minority." So, he warmly greeted me handed me my beverage but spoke in a subtle, artificial dialect and made word choices that he assumed people of my ethnicity regularly are comfortable with -- possibly in an innocent attempt to make me feel pleased with him.
But it had the opposite effect, as his behavior ended up treating me differently than other people because of what he perceived to be my ethnic background. He shouldn't have tried to sound Mexican if he's not Mexican (whatever that means); the barista shouldn't have tried to sound black if he's not black (whatever that means). He should just be himself.
Starbucks should create a script for employees and teach them how not to veer from it in inappropriate ways, lest they tread onto the slippery slope of casual racism. Maybe his behavior wasn't innocent at all; perhaps it was his way of resisting/protesting political correctness in the workplace.