I'm still alive folks and I'm wondering...

Why do some coworkers just get on your nerves? I love my new job, but it seems like there is always one person who'll just get under your skin every time. This person is young, fresh out of college and is as naive as a 3 year old. It doesn't matter if I'm on the phone, talking to someone in my office or clearly busy, she will just walk in and stand in my doorway or join in with the conversation. She may even choose to sit down for a while. I can flash her an ugly look and it doesn't matter, she still thinks it's ok to barge in. I was on the phone for almost 10 minutes one time and she sat in my office until I was off just to talk to me about her back hurting. What the heck??? One time I was having my weekly meeting with my supervisor and she yells across the hallway about something that I had just said. I yelled back to her "How did you get in this conversation?" I'll have a conversation with another coworker and she'll walk in, sit down and listen. We stop talking every time and she just doesn't get it. Which leads to another point I have to make about her. She's in everyone's office so much throughout the day that she works late everyday to catch up(I'm sure she looks like the good little worker). At the end of every single day, she's making it known that she needs to work late to finish this or that. I want to say "Only because you don't do any work during the day!!!" On top of all of this, she likes to brag about being a hoochie! I called her that one day and she said "that's what the guys from the football team call me." I just can't stand her! I usually can tell coworkers in a nice or jokingly way when they are irritating me, but I can't with her. What should I do besides pray for her? I don't know...