From what I remember of my days in the torture house, sounds like they haven't recalibrated the grinder when a new barista goes onto the machine, which they're meant to - otherwise the coffee can taste burnt or watery, depending on how fine the grind is. Also, the water is probably too hot and it's burning the coffee.
Basically, staff dont know what they're doing so either go elsewhere or keep buying lattes. I go to starbucks now because they're all lovely and white mochas are a great sugar/caffiene hit.
I am considering getting an aero press, heard lots of good things!