Have you as a deaf person ever been asked by an interpreter how he was doing? It's a normal part of any conversation, whether it's interpreted or not, to get what is called backchannel feedback, signing or saying things like, "Oh really?", "Interesting", "How awful!" This shows the speaker that you are listening to her and she is making some impact on you. Some deaf people will do that to an interpreter and some won't. An interpreted message is a little different from a direct one and I could see why a deaf person might sit there and feel like she is watching a television program, but don't forget an interpreter is a person who is trying to communicate with you. If you could give interpreters backchannel feedback, they would be better able to assess where they are succeeding and where there is room for improvement.
I don't mean to say that it is the job of the deaf person to critique the interpreter. To critique the interpreter would require years of training and access to both languages. Some interpreters want this and it's just inappropriate. The reasons they ask are that we interpreters only receive the basics in our two-year and even four-year programs. There is so much to learn about ASL, English, Deaf culture, American Hearing culture, and the world in general! We may attend workshops, we may socialize with deaf people, but for the most part we work alone with hearing people who don't understand whether we are doing a good job, and deaf people who can not compare our interpretation to the original, or they wouldn't need us there in the first place.
So if an interpreter asks you how they are doing, perhaps you could agree to give them more backchannel feedback during their assignment, so they feel someone is listening and don't forget to stop them when you don't understand them. It may be that the speaker is being unclear, it may be that the interpreter is being unclear, but either way you have a right to understand what's going on. The interpreter will start trying harder, you the deaf person will hopefully get a clearer message, and the speaker will have more success at whatever his goal is. Everybody wins!