At what point should you be honest with an acquaintance?

I have an acquaintance. Mostly we are just facebook friends. We go to a bar a couple times a month together. She vents. Constantly. Pretty much she's fun to get around when I get upset with anything b/c she's always so drama and her life is always 10 times worse in her mind. But one of those people you can't be around too often b/c she'll bring you down.

She is in school. Nearly every week she gets into a fight with someone in one of her classes and is asking me what to do about it. I know exactly what the problem is. She's from NY and for some reason a huge amount of people from NY start a lot of sentences with "In NY, we...". But this is the south and a lot of people would specifically NOT do it the way they do it in NY.

In her case, she says "everyone" a lot when she's angry. Everyone from this state is so stupid. In NY no one is like this. Everyone is a no account hick.

Well it's fairly obvious why that's offensive to people. I just laugh it off and try to remind her that she means everyone in her class or everyone she works with but I understand why people get pissed at it. She doesn't seem to understand that she's insulting the people she talks to when she does that even if they aren't the ones she is mad at.

Usually I don't say anything b/c she's just venting but as this happens every week and seems to bother her a lot, I've wondered at what point is "Why are people like that" an honest question? At what point in a friendship would you tell someone what they do that may cause a lot of their problems in life? It's the same thing with her dating life. On a date she tells the guys that all men are dogs and cheat on her. Every man is an ameoba on fleas on rats. Well if they guy is willing to hear that all night and ask you out again, chances were he wasn't listening--and is a dog who will cheat.

But when a lot of people vent they just want to air their grievances, not hear any advice. It would be different if we were really close but mostly our friendship is based on venting (I go to her first if something pissed me off too). Would you inform an acquaintance that this particular behavior might be the cause? But since it's so obvious, I can't be the only person to tell her that "everyone" includes...well...everyone.

After the 7th time she pleads "Why does this keep happening to me?" I'm beginning to think it's a real question. HELP!