In many situations, we lean towards writing an email, although a short phone call be more suitable. This is particularly the case when facts must be discussed and the pros and cons must be brought to light. In this kind of situation, communication by email is a waste of time. What will be clarified in five minutes by telephone can sometimes correspond to several days of email exchanges.
Before sending an email, you should always consider whether the conversation is likely to lead to conflict. Writing an email, professional or otherwise, in anger is generally a very bad idea. In such a situation, it is also strongly recommended to favor oral communication, in order to prevent the situation from escalating and eventually deteriorating. Look for personal dialogue and make sure that your interlocutor does not misinterpret your words.
Anyone who sends a professional (or private) email should also be aware that the content may be saved for a certain period of time. You have no control over what the recipient decides to do with your email, where they save it and to whom they forward it. Thus, you should always think carefully before writing sensitive data. Even when you are convinced of the integrity of the recipient, email remains a security risk: in order to avoid spying by third parties, you should secure your messages by encrypting them with SSL or PGP.