Speaking of annoying LEDs, I invented something called a DED- it’s a Dark Emitting Diode. I plan to use it as a “Power OFF” indicator. So instead of using an LED to show power on, we’ll start using the DED to show that the power is off.

Blue is a bad color for indicator lamps on electronics or other devices and appliances. Especially when they're small dots or otherwise a point-source of light.

The reason is that short wavelength blue and violet light is the hardest for the human eye to focus on.

First is Rayleigh scattering, short wavelength light scatters more, same reason the sky is blue.

Second, is the "rods & cones" of the retina in your eye. Of the color cones, blue is the lowest proportion, only 10% of the total. In the center of your vision, the fovea, the blue cones are only 2% of the total. The blue cones in your retina make up for this by being much more sensitive than the red and green ones, and the processing the retina, optic nerve, and the visual cortex in the brain does. Net result, blue can be difficult to stare at and focus on.

Third,  chromatic aberration in the eye. From the cornea, the lens, and the vitreous humor (your clear eyeball gel)  and more scattering make blue light have the worst focus in the eye. Chromatic aberration is where an optical lens doesn't quite focus all colors equally. And the ends of the visible spectrum are either shallow or deep of the ideal focus point. And blue (and violet) is on one end.

Fourth, LED's (not counting "white" LED's"*) put out one specific color frequency in a rather narrow band. Generally, the human eye/brain is used to seeing colors that are multi-wavelength like fire, or full spectrum/continuous spectrum white light, such as incandescent bulbs, or sunlight. So LED's can look unnatural and irritating, especially in shorter wavelengths.

*"White" LED's as noted above in the thread are actually blue or violet LED's with a secondary coating of yellow, green, and red phosphors that absorb some of that blue LED light and re-emit their own color. The mix of colors averages out to look white-ish to the human eye. Some white LED's have just yellow phosphor and the yellow mixed with the blue gives that "cool" bluish white appearance. Some have red and green phosphors included and have a more "warm" white look.

I think some people are still irritated by white LED's because they're just a few distinct frequencies of blue, green, yellow, and red light just averaging out to a pseudo-white, as opposed to a continuous spectrum white from sunlight or incandescent lights.