When there are constantly messages received on the phone by many different people, the mind acts in a very bad manner. It will start to treat these SMS, subconsciously, in a "take-for-granted" manner. It is quite understandable because, unknowingly, you know that(or perhaps, expect will be the word) people will message you. Except perhaps, from the people that you are interested in, then only you will take extra care in replying to them. Yes, it may sound tiring trying to treat every message you received in a more sincere manner. But, others do appreciate it.

It is somewhat different from someone who knows no one is going to message him. If someone does message him, i guess he will treat that person with as much importance as the meaning of the message.