New Rule for the universe!
When in a public restroom, you are NOT allowed to talk to your stall neighbors.
Apparently, this isn't some instinctively understood code of behavior. I have had this happen to me THRICE in my lifetime, the third time being today. And I'm only 27. That means, if I live a slightly longer than normal life time, this could happen to me nine times. That is nine times too many. So I'm taking a stand. Talking to the person in the bathroom stall next to you is NOT ALLOWED. And yes, [name removed], this rule applies to sisters.