Hell, it doesn't stop at HS graduation. I have met many, many bitchy women while in the workplace. Women, in general, are simply nasty to other women --- and, age doesn't matter.
You're right about that! I've been lucky enough to avoid the catty, soap-opera atmosphere women can create in the workplace, but my husband had a job that was a real Peyton Place.
For some women, the bullying and manipulating never stops, but thank God most of us outgrew it. I call these adult bullies "Drama Queens", who thrive on turmoil and intrigue and weird forms of "revenge". I simply don't put up with it as an adult.