We finally have an answer: The beginning and the end of the sliding motion that produces static electricity experience different forces – resulting in a charge differential between the front and the back that results in the crackle of static electricity.
If there was ever an argument against intelligent design, it’s shit like this.
See also the giraffe nerve that takes a 15 foot detour because it didn’t evolve to go on the other side of their hearts. It’s theorized to have travelled even further in dinosaurs:
(Source)