Yes, someone can interrupt your WiFi signal. There are a few ways that this can happen. One way is if someone is using a device that emits a strong radio signal, such as a microwave oven, which can cause interference with your WiFi signal. Another way is if there is a physical obstruction between your router and your device, such as a metal filing cabinet, which can block the signal. Finally, if there are too many devices trying to connect to your WiFi network at the same time, it can slow down the connection for everyone.