I would have to say that my biggest pet peeve is call waiting. I believe it has to be the rudest thing in the world to be having a conversation with someone who has another call coming in, they ask you to hold on, they check it, then decide that the other phone call is more important than the conversation you are having right then. It's rude, inconsiderate, and makes the other person feel less important. I do have call waiting, and the only time I ever switch over is if my husband is calling, and other than that, if it is an emergency, they can call my cell!
Okay, I feel a little better now that I have vented.