Two weeks into our first year in college, a young prof (probably around his late 20s) stepped into the classroom for our English subject for the first time looking hungover. He wasn't really hungover, he just looked like it. Maybe he was sleep deprived. So he walked in, went to the desk and looked around the classroom. He started throwing questions and was very disappointed when not a single one of us could give him a clear answer. Can't blame us; we didn't know what the hell he was talking about. When he was about to write on the white board, he turned back to the class and asked, "What class is this?" We told him our course and year. Then he threw the marker to the floor, sat on the desk and shook his head. "This is so embarrassing." Turns out he walked into the wrong class. Spent the rest of the period talking with us about random stuff.