The sound of water flowing under my house (a ruptured water line that was technically an easy fix, but tough in execution).
The high RPMs of my car engine coupled with a slight grinding noise that indicated my transmission would no longer function in this world.
The snap made by my neighbor’s leg as she broke her femur.
Inspiring ire, not terror: the whizzing sound of the dog peeing on the carpet.
The snap/pop sound with added blue flash that indicated water in the junction box feeding the water heater.