Do you take the machine gun approach to leaving a voicemail?

Or are you thoughtful in the message that you leave, encouraging with your tone of voice, diction, speed, and message for the person to call you back?

This is a drastic example of what not to do.. 

1) Who are you?

2) What are you calling about? ("What's in it for me?")

3) Phone number given, twice, at writing speed.