I don't know if it's my glasses or my eyeballs, but the common, cheap, blue LEDs that you see on cheap electronics nowadays are really uncomfortable for me to look at. If I buy so much as a usb charger with a blue led it gets electrical tape over it.
It's obvious that not everyone shares this phobia, but I can barely look at machines where the general illumination has been replaced with blue LEDs.
(Even in photographs, where the blue doesn't bother me, I don't understand the point. It just washes out all the playfield colors.)