It was supposed to be muted because we were eating and I heard someone take credit for some of my hard work. I looked at my boss and I said very loudly with a mouth full of food "Who is this fucking asshole? I've never met him, he's never done anything on this project. What office is he in?" There was a long pause of silence until some else said that the call was over and everyone was disconnected. I thought I was going to be fired and so did my boss. Ended up that a partner and the client found it hilarious and I got promoted. Found out later the other person got in a lot of trouble and was from some marketing analyst group in a different city.