Freaky Saturday

Okay, so here's some weirdness for you. When I left for the bus stop this morning, the microwave dial was set to the highest setting (which is where I always leave it). When I got back today, it was set to Defrost. The really weird thing is that this is the third time it's happened since my roommates moved out. Freaky! Nothing was stolen, though. The last time it happened I thought it might have been myself sleepwalking, but this time it couldn't have been me. What's going on here?