A Starbucks barista lists the worst type of customers Working as a barista at Starbucks allows you to see firsthand the stupidity of some people. Here are the 6 worst examples, according to someone who worked there (H/T AOL). "Is this drink mine?" "Saying Frappe" "Not saying what size" "Ordering while on your phone" "Dumping coffee into the trash" "I want that iced"