Never Think You’re Entitled to a Reply Unless it’s Realtime

A doom-saying report courtesy of news-medical.net says that "Mobile-phone addiction in teenagers may cause severe psychological disorders." That's nothing new to me, since addiction in general causes psychological crisis. What I find hilariously disturbing though is:
Many of these people take a real offence at not getting a missed call or a message answered, which makes them feel "deeply upset and sad".
If your message is really important, you should call your friend up or visit him. real-time communication will always be a more engaging, making for a more enjoyable experience. How exactly does a text give your recepient the incentive to reply?
Of course, if SMS or dropped calls are your only means of communication, then I'd say the grievance is justified.