my flatmate once had a guy round who was using our bathroom the following morning - I didn't realise he was in there and our bathroom didn't have a lock so I was walking through the hall and pulled the bathroom door open wide about to go in and there's this random stranger sitting, taking a poop in my bathroom.
So, obviously embarrassed, I quickly said "Oh, sorry!" and closed the door again - however, my cat (who was a little kitty at the time and had [and still does have] a thing about bathrooms i.e. she loves them) ran in when I'd opened the door and I couldn't really stand there with the door wide open and coax her out so I had to just close the door and seal them into the room together. I'm sure they bonded.
Also, any time I've heard my flatmate have loud sex - awkward.