What an end to a pretty good day...

I'm still debating whether or not to change jobs. I'm not ready to go back to school and change careers, it's more of a "job" for now. I've realized that since my kids are older now, I can go back to work full time. My family can definitely use the money! I go through ups and downs at my current job (as we all do). I only work part time but the hourly rate is pretty decent. There isn't room to grow with this company as it's pretty small, but it's convenient to home and the hours are flexible. The real downside is that many of the people I work with have no sense of professionalism whatsoever! I have problems. We all have problems. I take whatever is going on inside my head and leave it at the door when I go to work. This, to me, is a basic skill of workplace etiquette and unfortunately many at my small office do not possess this skill. We have one who slams doors, another who constantly complains that she hates her job and wants to be fired (if she quit she wouldn't collect unemployment). The owners of the company don't set a great example either, with constant mood swings that can make any employee go mad or even want to quit. I usually walk around with a smile and a sarcastic joke to lighten the mood. Who wants to be round so much negativity? Anyway, one person (not mentioned above - yes ANOTHER person) has decided to make me their target. They like to think that they can tell you what your job is and how to do it - all with an attitude. I don't answer to them. I refuse to be treated with such hostility that comes from nowhere. This person has already been reprimanded for their behavior and the way they talk to others but I fear it's just getting worse. I'm not sure what my next step should be. The only person above me is the owner. If I go to her and report the latest problems, do I look like a tattle-tale? Should I pull this person aside and kill them with kindness asking what can we do to resolve whatever the issue is? Should I take them out back and kick the crap out of them? Not sure, but the last one seems like the most fun for me! Unfortunately their are going to be assholes wherever I work but I'm not sure in such a small space I can take it anymore...