Voicemail Ettiquette

I don't know what it is about voicemails, but I hate checking them. I think it has a lot to do with the following things that I believe should be common knowledge amongst all adults, more specifically, those in professional business settings. The following are my top 3 voicemail pet peeves.

• I hate when people leave their call back number, but say it too fast or so inaudibly that it cannot be understood. No returned call for you.
• I hate when people wait til AFTER the beep then decide not to leave a message. If you're not gonna leave a message, hang up before the beep. 
• I hate when people leave a message saying, "It's important!" when it's really not. Please note that the word "important" now lacks significance when it emanates from your lips.

Is it just me? Or do you have voicemail pet peeves as well?