A: Well there is this whole knowledge of writing mails and answers, but i think in todays time writing emails is a bit different. It also depends on the person you are writing to and weather it is a first email or an ongoing conversation.
to start with i think emails should always be respectful, formal and conservative in terms of language. But as you get to know the other person, emails could become conversational, casual and fun.
remember many people now access mails on phone, so the language needs to be crisp, as short as possible, direct to the point. if mail is long..it needs to be mentioned upfront. the objective of the mail should be clear if not in the subject then in the first line of the email. So the receiver can decide if he wants to read it later. remember they might be in a meeting or driving when they get it.