I do see individual pixels on retina screens but I don't notice them on more organic stuff like movies on my screen. I guess computer content is just perfect squares and then perfect circles and fonts with some jaggy edges where they're rounded off, which is really not that hard to spot on retina screens. The difference between 4K and 8K in my opinion is that you can better see little glimmers, textures and things like that. But the 8K demo movie of course was highly optimized to show exactly that.
What I really like is HDR on true black OLED, killer feature.
But what I want more than anything is a "compression" feature on the audio of movies. I mean I just want to hear what people are saying to each other without the neighbors calling the police when going into a scene with explosions and/or music. I'm using subtitles in English for English movies nowadays FFS!!!