It can however be therapeutic to type the message. My trash bin is filled with email arrows that I am now happy I did not let fly. These are two common methods often used in email. I would discourage the use of these devices in business or professional email. These devices are best used in personal emailing.
Emoticons are punctuation devices used to convey emotions.
Business and professional email communication often require precision so acronyms should be avoided. It is common for the recipient to not understand the meaning of the acronym and therefore does not understand the message. Acronyms are very common in the law enforcement and investigative communities but differ from state to state or region to region. Your email program is usually defaulted to automatically quote the email to which you are responding. Cutting and quoting only that which is germane to the present issue is good form or proper Netiquette.