That vid was very interesting. I'd recommend anyone to click on that and watch it, genuinely a really good insight into what's going on in the background of our beloved gameHonestly, this video from a couple months ago was an eye opener.
Source: https://www.youtube.com/watch?v=dIc0WPY63hY
Short version: Silly things like rendering the eyeballs of NPCs inside a ground station whilst you're in a spaceship up in the atmosphere.