I won't deny that I do this sometimes, but I consider some circumstances on why I analyse a text before I send it. And besides, it's not like the person who will receive my text has no other things to do or doesn't have a life to live so he or she would rather wait for my text. Because we shouldn't rely on our cellphones too much.
On the other hand, sometimes we do need to think carefully of our texts especially if we're sending it to a superior at work or employer. So we don't text them like we're texting our closest friends.
At the end of the day, it's all about being responsible on how one communicates--be it in text, call, social networking sites, the rest of the internet world, or in real life.