Unfortunately, a very high percentage of people have NO understanding of what their breed is all about - good, bad or indifferent... they just go based on looks when making the decision, which is why so many good babies (any breed) end up in rescue, shelter or on the streets. I use to work at a dog daycare and I can not tell you how many people would say to me "I can't believe how high strung my lab is... my Jack Russel is, my German Shepard has so much anxiety, why? The first question any of the trainers in the facility would ask is ... what was the reason you decided on this breed?' and every time the response was one of two... they are just so cute or we grew up with the breed, always had one. My point it, the owner of the EBT most likely bought on looks and did no research so he was surprised by the behavior cause at home he is most likely a very good dog because no other dogs are in the home.
If you, as a responsible dog owner, want to learn the signs... there are a few books listed in the training and behavior section at the top of the page they are sticky treads.... read up on dog body language. That is what I was taught by the trainers at the day care --- it is all in the movements and somewhat in the sounds, but they tell you everything in how they are standing or moving, heck even not moving.