If you receive good night message?

This is the first time I heard this about friends saying good night on the cell phone. But I do have a best friend who lives in another state, who I knew since childhood, and we communicate via email often. Email is free and I'm not much of a phone talker. My best friend is a single mother and she checks her email and responds during the evenings and she often closes her email with "good night". I like emailing because it's relaxing and you can communicate during your own convenience. The downside is that you don't hear the person's voice on the other end, but that's why we have emotions and LOL so you can set the tone of the email. We also email our in-laws in another country often, instead of talking to them over the phone.

Hello,Vimaal! If i receive good night messages in my cell phone during late night it will mar my good night sleep.so i keep my mobile phone off at I.00 AM.i would not like to sacrifice my good night seep for good night massages.thanx.