First year of college, I was in a triple, one of my roommates was trying to join a frat and all of his secrecy/antics were super annoying. He would come back into the room every night at 3 am, lie around in bed playing on his phone until 4:30 am, get dressed and leave to go run laps around the campus as part of his initiation. This went on for like 2 months, he was also building some kind of weird statue of an animal for the frat and we couldn't know what it was so he would ask me and my other roommate to leave the room and not come back for like 2 hours sometimes.
On Fridays and Saturdays, he would leave to go to the frat house but he couldn't tell us where he was going. So one night, I decided to secretly follow him, I stalked him for like 15 minutes and took pictures of him entering the frat house. I sent him the pictures and he got so mad that he didn't talk to me for like 2 weeks. I also had these powerlifting smelling salts and was worried that he'd dump it in my face when I was sleeping, so I had to make sure he was asleep before me at night for a while.