As more people become interested in specialty coffee, a new phenomenon has emerged in cafés: some customers, armed with scattered knowledge picked up from training classes or books, observe the barista's every move throughout the process and even offer pointers on the spot, leaving many café owners on edge. Compared with the old days of rival cafés coming to challenge them, this enthusiast-style nitpicking is actually more of a headache. Drawing on several real accounts, this article discusses what to keep in mind when visiting a café, what baristas should do when they encounter someone intent on challenging them, and how to give feedback on a cup of coffee that doesn't live up to expectations in a way that is both sincere and appropriately measured. [more…]