My Life Questions

Voicemail

One of the greatest, most convenient things ever invented is Voicemail. Can't get a hold of someone? Leave a voicemail and they will get back to you. In your personal life you're lucky enough to chose whether or not you want to return someones call  but in the Work world it's expected that the call is returned A.S.A.P.
Here's the thing though, work people get lots of voicemails, they are busy people...but the will eventually return your call. Whats the point of calling them 14 times and just hanging up when they dont answer? It's a waste or your time and theirs. How is it that people can be so impatient. They're busy people too who I'm sure, can't always return phone calls right away either.
This is why I could never be a secretary. I have a friend who's one and people, from what she says, are really rude to her when they get a voicemail and not a person.  "This is not acceptable" one man said to her. Another man even swore at her and called her stupid because his salesman was not around. It's insane! Leave a voicemail and be mad at them, not the girl who runs the phones.

So my question is:
Why can't you have some patience and use your manners with receptionists...and then leave a voicemail?