Although you are upset because your boss wants to have the last word in email, isn’t that exactly what you are seeking? Just like you, your boss most likely believes that his closing words undercut any proof you can offer, and he probably believes that he is right and can prove it.
The problem is that if you both are using email to argue over who is right, you are both wrong. Email is not the right medium to be used in these kinds of situations. Email misses or distorts some of the most important elements in the communication process, such as tone, body language, and feedback.
Email can be highly effective when it comes to facts, figures, and specific information such as dates, times, and confirming data. However, when email moves into the realm of arguments, emotions, or personal matters, its effectiveness is virtually deleted.
If you want your boss to change, you should change the communication channel. The next time one of these debatable situations arises, try using the telephone or even an in-person meeting. By doing so, the discussion is far more likely to focus on lasting communication, rather than having the last word. | 
