for me, the ultimate father of all cringe is this:
when someone is defending and supporting an idea that i agree with, but they do it so poorly or act so off-key while doing so, that their actions will from then on associate people that hold that idea, even the most reasonable ones, with whatever foolish antics that the particular person did.
i cringe the entire time i see something like this go down, because i know it puts a weight on me and others like me.
Avery Brooks', DS9's Captain Sisko, acting when attempting to be passionate about something, which Sisko did all too often. He just sounds like a pompous blustering jackass who's got something threatening to pop out of his ass.
I cringe really hard when someone whines and moans and complains about an artist drawing the genitalia of an animal in non-sexual art. As if it were a crime to honestly render a picture of an animal like they naturally are. Even totally platonically, without any sexual intent at all. You know you're in a screwed crowd when depicting the unaltered animal body is seen as a bad thing, and it is assumed by default that you would instead draw a sexless modified version tailored to an entirely unnatural (maybe even anti-natural) 'pp is icky' way of thinking. A way of thinking which attempts to infect other animal species with the same perverse modern human taboo against mere body parts.
If you get mad at people drawing a subtle sheath on a horse painting, wait until you find out that all male horses actually have sheaths then you'll go reeling into a hissy fit that'll have you convulsing on the floor.
Either put a blind fold on, or have every animal forcibly neutered to your liking. It's the only way.
Also...when writers assume too much that the audience is daft and feel the need to explain the plot to everyone and in doing so always begins the exposition with "As you know..." Which is stupid. If the character already knows, as those words indicate, there should be no need to explain anything.