Privacy for sure.
If it's anything toilet related, I'm locking that door
If it's a shower, I don't mind if she walks in to ask me something or get something out of the bathroom. I have a young daughter, so if I'm showering she may need to "use the bathroom" so I'll allow that [I'll cover up with the curtain haha], but otherwise it's a locked up situation for me.
If it's anything toilet related, I'm locking that door

"Be Excellent To Each Other"