There are a few things that come up to my mind.

I always hated to see adult women dressed like young school girls or seeing children's toys in the background. That has always been a total turn-off for me.

I hate guys shouting that they are coming before they even have a hard-on.

I also hate shaking cameras, poor lighting and poor camera angles.

I hate guys - actors or crew - blocking the sight.

I absolute hate dumb talking during a bukkake or gangbang scene.

Growing older I realized that I now hate to see if male actors treat the woman respectless. It is hard to explain. Don't get me wrong, I often enough like scenes were the female is submissive. But I think that a naked and tied-up woman kneeling in the company of several men can still be treated respectfully in porn.

In bondage or BDSM stuff I hate it when they use ropes or chains strong enough to tie down a tank on a flatbed car or so much rope it would be enough for a sailing ship. I hate it if there is too much of toys, tools or other stuff, distracting from the woman.

With facial or bukkake scenes I hate it when they cut the scene the moment the woman has received the last drop of sperm as I like to see the woman afterwards with all the cum on her face and body.

I also realized that I don't like settings like a sterile studio or filthy backyard.

It seems that I became a grumpy old man over the last years.