Guys who have star-of-the-scene-itis. They won't shut up, do stupid moves like put their foot on the girls head so their entire leg is blocking the girl in the shot, etc.
And honestly, just all the tats in this day and age. Someone like Skylar Vox coulda been top ten all time for me, but then she got fat, started getting giant black ink blob tats, etc. And she was already in the frustrating category for me, alongside someone like Kenzie Reeves (who also has one of the dumbest tats of all time that made porn producers and directors make her wear a shirt pulled up for her entire career's prime) due to the horrendous, ratty ass wigs they always wore too. This should be the golden era of porn, HD wise, and quality of girl wise, but they seem determined to ruin it with a million tats, dumbass septum piercings, and awful wigs or dyed hair... someone like Lily Lou was already a smokeshow, but now she's doing that hot pink nonsense, I just find it all tiresome and offputting.
And as someone who enjoys lesbian porn too I'll agree with the poster above me... watching a girl suck on a dildo or strap-on is the stupidest shit I've ever heard of. Literally no one is deriving pleasure from that!