Ignorance

Yesterday at work, I'd just finished some dishes in the back and with my arms full, headed back out front to put them away. A woman was standing by the cash register so I said "Hello" so she would know I saw her. I figured she'd put 2 and 2 together and realize I'd be with her as soon as I put down the dishes that were in my hands. WRONG.
Even with my backed turned to her, 8 feet away kneeling down to put them on their shelves, she starts ordering. Seriously? You can't wait 5 seconds until I put these down and am actually facing you asking your order? So I quickly put them away and asked her "You said you wanted a Tall Vanilla Latte... with what?" I was very polite. By this time she on her cell phone and couldn't be bothered, having a loud conversation about someone dating someone else. I HATE when people do this, not just because it's rude, but what am I supposed to do? I feel like I'm invading their privacy because I'm overhearing their conversation. I feel like those nosy old people in the commercial for Loud N Clear that are creepily in the background spying on their neighbors. So I just kind of avoid eye contact and try to pretend like I'm not listening, but who am I really fooling? NO ONE. People like this deserve to be slapped and I'm more than ready to volunteer for the job :D