1. My name is Robert. I introduce myself as Robert. It irritates the hell out of when I introduce myself as Robert and someone automatically starts calling me Bob or Rob. To me it's just rude.
2. If you're standing at the cashier at the supermarket and he or she is ringing up your items hang up the damned cell phone! You're doing business with someone, give him or her your undivided attention. It's rude to be chatting (loudly!) with someone else at this moment. I have and will tell you to hang up the damn phone because no one else wants to hear it. And if you're the cashier don't be chatting with your friend in line behind me while you're ringing up my items. Seriously, I've complained to management about this...