system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why, when looking at a computer screen from a lower angle, do the colors invert to a weird blue and black?
gpt
A computer screen is made up of pixels. There is no single LED/crystal/light source that can display all the colors you want represented as a single piece.  Instead, there are multiple sub-pixels in each pixel.  The most common is to have one Red, one Green, and one Blue (RGB).  They adjust the relative brightness of each sub-pixel to mix RGB colors into the final color you want.

The sub-pixels are all meshed together in grid pattern.  Something like

      R
    G  B

Additionally, each pixel is surrounded by a mask to prevent the light from one pixel bleeding into the next.

Each pixel is optimized to cast light forward, towards you, the viewer.  Imagine you had 3 christmas lights, red green and blue, at the back of a toilet paper tube.  If you were looking directly at it, you could see all 3, producing a white light effect.  As you tilt the tube, there comes a point where one is blocked, and then a point where 2 are blocked, changing what color of light you would perceive at each point.

That is essentially what is happening when you look at a flatscreen from outside its optimum viewing angle.  The mask around each pixel is blocking one or more of the sub-pixels from your vision, preventing you from seeing that part of the color.  Different flatscreen technologies (TN vs. IPS vs. AMOLED) and different production qualities within each of those will result in different optimum viewing angles.