Signs that some patients may oresent with upon arriving to a scene can range from severe anxiety, panic, sadness, high strung, combative, or even overly friendly. You as a EMT have to be mentally prepared to deal with any and every kind of emotion their is. You are going to see it all from patients out in the field. Your communication needs to be at its best because you are working with people who need to hear from you. Sometimes that can help smooth the process of a situation or calm a scene, you just never know.
As a EMT you must be careful what you say at all times. Certain comments or harsh truths of a patients status or condition should be avoided. Don't give false hope, but rather try comforting them in other ways such as saying "you are doing everything possible to help them" or "I won't leave your side". That can mean everything to them, an it also helps you perform smoother on the patients.