The problem with 12 minute voicemail messages is that they are loaded with other issues. Usually culprits are: rude and smarmy, saying things to your voicemail that they wouldn't have the balls to say to your face, are completely incapable of considering the comforts and rights of others, and are d-bags. These kind of people include: ex's, in-laws, friends going through the same break-up for the 5th time (I file this under temporary insanity) and some landlords.
Sometimes people get really excited about something and forget to stop talking, if you have left a message where you have been cut off due to length of your message it is your DUTY to call back and BRIEFLY apologize (no need to be a repeat offender).
Moms are universally excused from this rule. It is not their fault because they simply cannot help themselves. They are the only people that legitimately have THAT MANY things to say and don't really need your feedback.