I applaud the "flush constantly" person - I always do that too! I don't want to hear your conversation in the restroom - most of the time, the half I hear is inane.
I don't get that - I've been at conferences and seminars where people go INTO the bathroom to use the phone. They're calling clients and office staffers.
I think it's rude towards the other users in the bathroom, too. There are people (not me) who have difficulty relieving themselves if there are other people in the bathroom.
It's just disgusting to listen to, esp. heavyset people who grunt and breath heavily as they try to juggle phone, skirt, and pantyhose. The acoustics are so bad, you can't understand the caller anyway.
If someone calls me from the restroom and I figure out where they are, I just "accidentally on purpose" hit END CALL. Ooopsies. Must have lost the signal in the loo, love. I do the same thing to people who call me from the subway or bus station just as the train/bus arrives. Yeah, I really don't want to listen to the metal wheels screeching and the kids shouting on the platform.
I think it's some sort of delusion if you think you're so important that you can't be off the phone for five minutes it takes to "go potty."