When you spend long hours creating
photoreal images, you learn a lot about what makes a scene look
fake. Many subtle things can undermine visual
realism: lighting discrepancies, color saturation, perspective shifts, etc. Most people can realize something isn't right ("that skin looks like plastic"), but when it's your job, you have to analyze why.
Now I'm sure this happens to many people, but for those I know in the
visual effects industry, it happens frequently...
You witness a scene in reality that looks "wrong". It's real, right there in front of you, but that feeling of non-reality is still triggered. For a moment, you see the exception that proves the rule. Through some unusual set of circumstances you get a visual false negative. Often the scene is so incredible to look at you can't help but to stare in amazement. Other times it just looks like pieces from two different pictures sloppily composited together. (Which leads to the inevitable comment when with VFX friends, "If I made a scene that looked exactly like that..." then chuckle.)
Now I just refer to those times as having a momentary simulacrum disorder.