One of the most difficult things to get used to, for me, is not interjecting your own opinions when interpreting.
As I have said before, when interpreting, you are supposed to be a conduit for communication. You are not supposed to be involved in the conversation. The only time you are allowed to speak on you own behalf is when you are unsure about the meaning of something. However, when you see two parties disagreeing about something and realize where the disconnect is occurring or hear someone lie about their situation, it is really hard to keep it to yourself. I often interpret situations where I can hear the issue that both sides are having with the other and I can see a great solution that would meet both of their needs. But I cannot break my role and start suggesting things. That is not my job and would actually make my job harder, because then I would have to be interpreting what each party said to me and what I said to each party plus what they said to eachother. No thank you.
There is also a good reason why we are not supposed to interject our own opinions. As much as you may think that the situation is simply a language, cultural, or point-of-view issue that you could easily resolve for your clients, it is often not that simple. People have ulterior motives. People have strategies that they employ to get what they want. Sometimes one party is saying that they can’t do something, not because they can’t, but to drive the other party to a preferable alternative. Sometimes, we just don’t know enough about the situation or technology to really understand the barriers to peaceful resolution.
Remember, disconnects happen among native speakers as well. Avoiding arguments is not part of your job.