Many people at work will hide out in the bathroom to make/take personal phonecalls as well as tend to personal "business".
I really do not like being in the next stall over knowing any noises will be broadcast nor do I want to hear their conversation.
I also have a friend who continues talking on her phone (from her house) while she goes outside for a cigarette or when she takes a bathroom break. About the only time I can fit a word in edgewise is when she mutes the phone to flush. Sure makes me feel like my participation in the conversation isn't very high on her list of priorities!
At least she isn't driving and talking on her cellphone.