...for reasons which should be fairly obvious.
Annoying...when someone calls my house and doesn't leave a message. I have an answering machine for a reason. You called me so you must have something to say. So you know, say it. If I have a message, I will return it, but if you call and don't leave one, I am not going to bother calling you back. REPEAT: NO MESSAGE FROM YOU MEANS NO CALL BACK FROM ME.
Even more annoying...when someone calls once, doesn't get an answer, doesn't leave a message and then continues to call repeatedly...and still doesn't leave a message. Obviously I am either not here, busy, or plain and simple don't feel like talking on the phone. Again, I have a machine for a reason.
And just in case we're not clear on what the reason is...its purpose is to take messages, so that I can hear them and respond accordingly.