I don't believe I have ANGSTed about this before.
My brother's room is connected to mine. This means he has to enter my room to get into his.
This means zero privacy for me. My brother has come quite close to leaving his room to find me changing my clothes over the years. I wish, if we're still living here for a few more years, that another door to his room would be created in the stairway corridor so he wouldn't have to breach my privacy.
It's also because of this I have no lock on my door. My door is also one of those old-fashioned doors that have a top and bottom portion to it that are separable, so one could easily peek between them to see what I'm doing. Sometimes, while I'm sleeping and my brother is awake, He likes to leave his room and go downstairs, and leave my door open (I prefer it closed most of the time) I awake to find my door wide open so I could hear everything going on downstairs to wake me up, blasting TV, parents arguing, etc. and I'd hate getting out of bed just to close it and return to sleeping (that and I don't wear much so someone could see me in what I'd rather people in my family NOT see me in).
EDIT: Post-script: It's even more annoying when my brother leaves the door to HIS room open as well, when he's in it. This further lowers whatever privacy I DO have.