But, Because, But

Yesterday, I was listening to someone talking on the phone to her client. At this stage I should write that I wasn't spying on her, but coaching her on how to communicate with clients more effectively. This particular caller wanted my student to provide some information, and my student was trying to explain that the caller had already received the information, as she had sent out a full explanation by mail last week. And so, she kept starting every sentence with "But you already have that...", "But I..." "Because you didn't..." "Because I already..."etc. I really didn't like the conversation.
What was my problem? Although I wasn't listening to the caller's statements or questions, my student was making it very clear that she was in oppositon to everything her client was saying. While I would disagree if someone told me the sky was green and the sea was blue, I wouldn't start my argument with "But". The word but is used to warn the receiver that the next statement goes against what we have been saying. It sounds strange, for example, to say "She's fit, but she's healthy", or "I don't smoke, but I don't drink".
Occasionally, of course, we do have to use "but", but when every sentence you use starts with "but", the overall impression you give is that you disagree.
We are then presented with the question of what we can replace it with. Well, why not just leave it out? When someone asks you for information you have already sent, just give them a fact. "I sent it yesterday as an attachment". The difference is quite large. If my student had removed the "but", her answer would have delivered the message that she had already performed an action for the client before the client herself had requested it. My student would have made an overall impression of one who delivers. Depending on whether my student was making any progress with her client, you could argue that it would have been better and more effective to just send the information again. If you're thinking about clear communication, it might also help to think about what you want to achieve from it. For example, if a client says that they will pay me if I send an invoice. I'll send the invoice. My aim is to get paid, not to prove that my memory is better than theirs. No buts!