“Hello” one would say after picking up the phone and the person on the other end would introduce himself or would ask for someone. “Hi! How are you? Have not heard from you in a long time. Where have you been?” This is a possible conversation that could happen over a phone. You must have noticed that one of the most important part of this conversation is the element of surprise. Now with mobile phones that element of surprise has just disappeared. Consider the same conversation now.
“Hello”
“What the fuck do you mean hello?”
“I beg your pardon”
“You sound so suspicious. Didn't you saw my name on the caller ID?”
“Hey man, it's been a long time.”
“What do you mean long time? Don't you check the missed calls on your phone?”
“Yeah man I love you too.”