This relates to something I've been arguing hereabouts since before the founding of Less Wrong. Basically, if you reduce all of your decision-making to a mathematical algorithm, then you're limiting the power of your decision-making to those parts of your brain that can do math. But our brains can do amazing things if we let them, and are mostly not very good at math.

a good cognitive hazmat suit

I want one!

the traffic light shimmered silvery-blue, like an arc of liquid electricity creeping across the surface, and then returned to normal.

I would wonder if something like that actually happened - it might have been an unfamiliar trick of the light or electrical malfunction...

Once I was walking down the back of West Rock at twilight and suddenly noticed everything was done up in strange, bright colors - the rocks were teal and purple, the leaves were emerald green, etc. After several minutes, the experience didn't go away, and so I picked up a representative purple rock and brought it back to civilization, thinking that would dispel the clearly hallucinatory magic. I immediately asked a passerby, "What color is this rock?", to which the response was indeed "purple". I resolved thenceforth to pay a little more attention to my surroundings.