If

If you care enough about someone, you will always have time to ask how are you.

If you respect the people that care about you, you will always have the time to let them know that you are alright. 

You have time to chat with your friends, check you Facebook and surf the Internet, you are for certain have a minute for the people that love you unconditionally and have given so much of their time for you. 

It is courtesy, it is respect.