I only became an Amiga owner in the 21st century, when it was all over bar the shouting, but friends owned them at the time and loved them. (I had an Acorn Archimedes with RISC OS 2.)

As I understand it, the weird colours of AmigaDOS 1.x (blue, white, black and orange) were chosen to deliver usable contrast on an analogue TV set. This not only means a blurry CRT, but also that, given where the Amiga was designed and made, it was an NTSC TV.

http://toastytech.com/guis/amiga1.html

I've never watched NTSC TV in my life but I remember the 1980s joke definition: "Never Twice the Same Colour".

They have a good excuse for it. They designed everything to look readable/usable on average home TV. Add the loss of quality in RF modulator and you figure the crazy colour scheme with ultra simple icons.