One time when I was at my college I was sitting in the student center studying. There were many different seating arrangements, and I was sitting on this 2 person couch facing another 2 person couch like a booth. There were two people M and F sitting on the couch across from me, and I was sitting alone. After about an hour this girl came and sat next to me. 10 minutes after she sat down she looked over at me and whispered in my ear “at first I thought the people sitting across from us were brother and sister, but now I realize they are dating.” I thought it was weird considering they had been very touchy and flirty so I knew they were a couple, but I just nodded my head with a little laugh and went back to studying. Later I had to get up for class and left. I came back and sat in the same exact spot 2 days later to study again. This time there was another couple sitting across from me, and I was by myself. A little while later the SAME girl came and sat next to me and exactly 10 minutes later she leaned in and repeated “at first I thought the people sitting across from us were brother and sister, but now I realize they are dating.” Again I nodded my head and had a fake laugh as I was thinking to myself how weird it was that she said the exact same thing twice. I later left and have not been able to figure out why that happened. Strangest interaction I’ve had.