I used to love texting (I have since switched back to instant messenger as that's where a lot of my friends prefer to talk).

That being said: Texting is an asynchronous communication style. As such, it does not require openings ("Hello & good morning!") or closings ("Have a great day!"/"Bye!"/"Catch You Later!"). Nor does it require you to disclose "Have to go to work, I won't be able to respond for a while." If someone is expecting a real time response, that conversation should be a phone call. All other communication, it's assumed the other person may not respond back for a while due to prior engagements.