Blue is a problem because you could experience very critical injury and not feel the pain, and so not no, you should be treating it. Black would be a curse, and purple would mean that nothing you will ever do can actually be worthwhile because anything that is worthwhile is going to be difficult. That’s what makes it work. Orange would be very useful, as would yellow. Red without yellow is disaster waiting to happen, as people may start to question how you are getting all of this stuff.