Thanks, yes I think you are right - there are many things that artists obsess about which the viewers usually don't notice.
Although my experience tells me that, even when I don't notice something directly, it can lead to the whole image being off. Photorealism is about the small inconspicious details, after all.
I also look at my images over and over again to analyze them, and there is a growing list of details that seem to be missing.
For example:
- saliva dripping from her gagged mouth and forming a little puddle on the floor
- sweat on the body (already used a geoshell but removed for the render)
- spanking marks on the buttocks
- the fists don't look clenched enough
- etc.