girls bathrooms are completely different from mens, in mens bathrooms you were trained to NEVER, EVER look at or talk to someone else in there, and you also learned to be as fast as possible.
Now, I didn't really act like a girl, or 'obey' the girls bathroom 'rules' but I can tell you what I observed.
Its ok to talk to your girlfriends when in the bathroom, usually while at the sink, and often girls will sit and chat at the mirrors and put on makeup or check their hair.
If you encounter a stranger in the bathroom, it is ok to smile politely as you go to your stall.
Girls tend to be more modest about their bodily functions, in mens rooms you are pretty much fine to let one rip, but in the girls bathroom you will get laughed at and judged (I had it happen to me once, it was terrible, ive also had it happen in the guys room and nothing happened)