People with no life: Phone-hangers

Have you ever receive calls when you are real busy, and when you pick up those calls, the other party either mumble some gibberish and hang up, or simply hang up after hearing an unfamiliar voice (your voice)?

Seriously, this people should get a life. Or maybe not so much about getting a life, but rather, they need to learn to be more gracious socially. I think the least they should do is to apologize if they have called a wrong number. Isn't that common sense? Apparently, it just doesn't seem like it's common sense to many people who are simply lacking in social grace.

Whatever...