Mechanical noise, unnecessary lights that can't be defeated, unusual output/input connector fittings and products furnished without a schematic.
What about a product can irritate you?
What about a product can irritate you, other than the sound?
I thought of this today while attemting to install a new pair of cables. The cables came out of the package in the shape of a Slinky and no amount of bending them, shaping them, stretching them or otherwise trying to reshape them would do any good... they are permanently shaped like a big telephone cord.
I find cables that aren't installation-friendly to be incredibly irritating.
Do you have a pet peeve?
Dean.