Paraphrasing my statements in a manner to completely change the meaning. If I take the time to give someone a precise answer, the LAST thing I need to hear is, "So, you're saying..." and then rephrase it to what they WANTED me to say. I can't help myself - I always have to respond with some kind of smartass comeback - "I'm sorry, but you clearly didn't follow what I was saying, as I most certainly did not say that" or something like that. And even worse is when they do it repeatedly - at that point I either tell them that no matter how often they incorrectly rephrase it my answer will remain the same and it was NOT what they said, or I respond with, "I'm sorry, but I can't think of a simpler way to phrase it so that you can understand it."
And do not interrupt. Period. Besides being rude, it also means that you are going to miss something I said - and I'm usually saying it in response to a question YOU asked. Present me the courtesy of finishing my answer; I presented you the opportunity to finish your question rather than trying to guess exactly what you are going to ask.