For a senior paramedic, a multi-car crash with people screaming all around is probably just another Monday, while I do get quite disturbed by seeing things that are supposed to be inside the body. Not that I couldn't stand blood, it's just wrong, and sets of the same pre-historic monkey alarm bell as big spiders and unusual amounts of fecal matter.

While I believe you can learn to push through most of that, different people have different tolerances for different things at different times. Plus, "I can handle this" is different from "I enjoy watching this right now". I would be pretty happy to have a gore warning when watching something while eating, for example. Or a warning about a super depressing story when I am feeling down anyway.