In this extract from "American Dad", we see good interpretation that could have been great. Akiko, the interpreter reflects Toshi, the Limited English Proficient speaker's intensity. Him slapping the air and her slapping the third speaker as a result is obviously a joke but the sentiment is correct - when a speaker is angry, it is a natural impulse to want to lessen the negative emotions for peacekeeping and the sake of the conversation's flow when in fact the opposite is required. Interpreters aren't supposed to be diplomats and diminish the messages interpreted; by doing so, they implicitly become a participant in the conversation. Despite the language barriers, most people will catch on to their interlocutor's tone thus diminishing or embellishing it only erodes the trust placed in the interpreter.
The major mistake Akiko makes in this extract is to use the 3rd person when interpreting Toshi's speech. This is another way for an interpreter to imply their involvement in a conversation as a participant and not just a means of communication between two people who don't speak the same language. The results are immediate and Toshi's interlocutor does not reply to Toshi but to Akiko herself thus changing the dynamic of the conversation.