So this happened to me a few weeks ago, and it still amuses me. 

So for context I live in a student dorm, and I share a kitchen/common area and bathroom with three other people. It's in the middle of the night and I'm thirsty, so I put on my bathrobe and pad out to the kitchen to get a glass of water. And I get into the kitchen and a complete stranger is sitting by the table eating McDonalds, at 3 am. I swear I jumped a foot when I rounded the corner and saw him sitting there, and he was all alone none of my flatmates was sitting there with him, so just this lone stranger eating McDonalds burgers. 

I probably just stared at him in disbelief for a few seconds, trying to figure out if this was real or a strange dream. 

Thankfully it turns out he was visiting one of the guys I live with, and wasn't some strange burglar. We chatted for a bit, or well he chatted and I answered with one syllable words and then I got my glass of water and went to bed. The whole thing felt really surreal. 

I met him again the next morning as I was preparing breakfast, thankfully actually wearing clothes instead of just my bathrobe. He on the other hand was just clad in a small towel... the life in a student dorm is an interesting one.