I love HDR and specially Dolby Vision. Can't watch anything without it anymore. On an OLED tv, it's phenomenal. Bear in mind Dolby Vision is made to be watched in a pitch-black room.
With OLED and Dolby vision, brightness is not uniform on the whole screen and it reproduces reality in a much better way.
You can see all the subtle details in dark areas and feel the brightness of a light source in another area just like real life. Twilight scenes are beautifully real with the dim colors of the sky and the vivid bright colors of artificial lights of buildings or lamp posts altogether. You can feel the light falling on characters faces and how the positioning and size of it's source are casting soft or hard shadows. Backlights look really real too, blinding you a little so you can't quite clearly see the subject in front. It's an amazing technology. With HDR and Dolby Vision, you can feel the energy of light and the void of darkness.
When I watch something in SDR or an old movie filmed in 35mm, I feel like the image is really lacking compared to modern digital Dolby Vision content. With Dolby vision, I feel like the action is right in front of me. In SDR or an old film lacking dynamic range and full of grain, I just see a rapid slideshow of old photos. It breaks the immersion.
HDR on YouTube though, I agree, it looks bad. They should call it SDR with the brightness knob set at 2000%.
