One of my pet peeves are annoyingly long voicemail instructions. Here's a typical one:
"Hello, this is the voice mail box for 415-420-xxxx. To leave a message, press 1 or wait for the tone. To send a numeric page, press 2. At the tone, please record your message; when you have finished, you can hang up or press 3 for more options. BEEP."
This kind of message is especially irritating to iPhone users, since in order to press the 1 key and cut to the chase,they first have to press a button on the phone to display the keypad, then press the 1.
How about the following alternative message:
"Please leave your message after the tone or press * for help. BEEP."
This is optimized for the 99% of the time that a caller just wants to leave a message, doesn't require any key to be pressed, and allows a power-user to get help if they really want it.