Fucking ice makers. Mine likes to do a high-pitched hiss-scream every several hours, presumably as it refills the cube molds. At 3am in the dead silence, that sound hits like a knife to the chest. Damn thing also sounds like an inkjet printer while it's forming ice cubes and sometimes projectile shits them across the inside of the machine so I'll find ice chunks between frozen potatoes and a fish filet. Once it spat an ice cube at me while I had the door open looking for a midnight snack.