Just because you have a cell phone, that doesn't mean you have to use it constantly. Use a little restraint and common sense, people. Does everyone in the dentist's office waiting room need to know every little detail of your ugly family feud? The fact that your 13 year-old is shushing you and is totally mortified should have clued you in. Does the entire post office need to know the intimate details of your recent colonoscopy? Even your spouse probably doesn't want to know all of that.
Just because you have a cell phone and it rings, that doesn't mean you have to answer it. That's what voicemail is for. You can call back. Do I really need to know that you're in the bathroom? I can't help but picture (cringe) what you're doing with the hand that's not holding the phone.
If you must talk on the phone while driving (I know sometimes it is necessary), please use a headset or hang up while you're trying to parallel park. Or is it just me that needs two hands and complete and total focus for that?