Trying. So many meanings.

It's hard being on the front lines everyday. I am really lucky that my boss realizes this--she knows how hard we try, how much we deal with, and how difficult it is to maintain a sunny disposition all day, every day.
I think I'm very forthcoming with her. I tell her when I had a problem, when I am feeling overwhelmed, and when I have probably been a bit more straightforward than I should be. I've admitted that I have a problem with always being nice. It's just not my style. I mean, do you know anyone who could be infinitely patient and kind and smiley for forty hours a week? No. Not unless they are taking copious amounts of drugs. Something I haven't resorted to yet, but it might be in the works. And this is why:

I'm on the phone. A guy is being very unhelpful about the book he wants--it has a green cover, it might be in science fiction, and he saw it on a table at the downtown store. Which closed LAST SUMMER.
I'm also alone, have four people waiting for help, and have another call on hold. A girl breezes up to the front of the line and says, loudly, "Where are calendars." I make eye-contact with her, indicating that yes, I see you need help. But I am otherwise occupied.
"Hello?? WHERE are the calendars?"
This? Is just rude. I AM ON THE PHONE. And it's not like I'm on a social call--I'm clearly listening intently and typing on the computer. I've now missed half of what this guy is saying because of her. I just...I can't explain how angry this interaction makes me. I am a person. I am on the phone. Don't yell at me. And this person I'm talking to? Was here first. He waited on hold. He is trying to find a book. He deserves my time just as much as you, calendar-girl.
I ask him to hold for a second, tell the girl that we don't have calendars anymore, and hear her say (she's been on a cell the whole time), "This girl just made a face at me!"
Yes. I had a look on my face because you are a rude, invasive, selfish bitch. You cut a line of patiently waiting people, interrupted me, and then didn't like my answer.

I am TRYING. I am not a bad person. I can be nice. Why do people have to ruin it?