Nerve-Wracking Neighbors
Riddle: Anna was watching TV in her house when she heard someone knocking on her door. When the woman opened the door, she saw a suspicious-looking man who claimed to be her neighbor. The man became nervous and said, "Oh, I'm sorry. I thought this was my house. I must have confused the houses,". Anna didn't believe it was just a mistake, and she called the police, saying that this man was a robber. How did Anna know?
Answer: If the man really thought that it was his house, he wouldn't have knocked on the door; he would've tried to open it with his keys. Knocking on the door is a technique used by criminals who want to break in and steal stuff.
Source: https://www.riddles.com/11455
