I'm sure you've heard this common mantra, "I never notice the recoil when I'm hunting."
Well, neither do I notice my flinch when I'm hunting.
If time permits, I will search for an explanation as to why I missed. I follow the bullet's path, find where the bullet landed. This season I found a fragment of rusty fencewire that was between the target and me. It was clipped and curled away from where I was standing. The ends were fresh metal and on one side I could see the traces of my lead ball. Sure explained why I found the dirt from my ball several yards short of the target. Another miss, there just was no evidence. Flinch? Maybe, I just don't remember though.
I shoot a flintlock. After enough shots at the range, the vent starts to foul and missfires show up. That reveals flinches pretty quickly.
I also noticed another type of flinch that isn't really due to anticipated recoil. Shooter's can pull off target if they are trying to watch the target respond. Just like a golfer lifting his head to watch the ball fly through the air, a shooter can lift his head to watch a water bottle explode, or a deer drop, or ...