Having posted on politics and religion, it's now time to complete the trifecta of topics that inflame fanboys by posting on a trope that I feel should be on TVTropes (if it isn't already there under another name) but I'm too lazy to write out and consolidate examples of.
Specifically, the Expanded Human or expanded definition of "human."
Any character in any work of fiction that is officially declared to be non-human but who looks and acts human in all the ways that matter is an expanded human, so I guess the TVTropes-friendly definition would be any character who has non-humanness as an Informed Attribute, but unlike Human Aliens, their resemblance to humanity is never acknowledged, or its implications are buried, or the audience is ostensibly expected to file it under suspension of disbelief, along with why the alien planet resembles the lot behind the studio or a rock quarry they got permission to film in.
For visual media, any character that is portrayed by a human actor without CGI is human, expanded or otherwise.
Likewise, any character that could have been portrayed by a human actor without CGI is human, expanded or otherwise, even if they were actually created entirely with CGI.
This particular trope is pernicious because even if you accept that aliens/gods/etc just happen to look human into suspension of disbelief and decide they're "supposed to be" different (but the budget didn't allow it or something), there are subtle effects that linger. For example, the basic premise of humans locked in a struggle to preserve/defend/build their society against alien interlopers has basically been done to death at this point, but in an example used above (namely, Avatar), the formula is turned upside down with humans declared the bad guys— and the only reason it works is because the "aliens" are clearly and unambiguously human. Swap them out for the aliens from, say, Alien, or Independence Day and suddenly the human society desperate for Unobtainium (yes, they actually called it that) doesn't seem so bad.
And then of course, there's all the hot romance with Green Skinned Space Babes that would be really disgusting except for the fact that the "aliens" are clearly and unambiguously human. Seriously, this is annoying. Would you be romantically interested in this? No? That's your closest evolutionary relative. That's not even this (which is at least a placental mammal), let alone this, (which is still a mammal), let alone this, (which is still a vertebrate). An actual alien is less related to you than THIS, (at least you share common descent). Yet more works than I can name include an alien love interest (it is, after all, a trope of its own) and no matter how committed one is to suspension of disbelief this leaves no other option than that the "alien" is, in fact, a bona fide human and is supposed to be that way. (Well, you don't have to assume it, but the alternative is unpleasant.)
And while this should get an entry of its own under LTTBM, it just bugs me when an EH character's non-humanness is stated, invoked, held up, or used to justify things narratively when the character never actually does anything that seems the slightest bit non-human. I suppose The Doctor from Doctor Who is one of the more prominent example of this, but Doctor Who gets a free pass on many things that bug me because it's So Bad It's Good; cheesy tropes and a budget of £10 per episode are what makes it what it is so the fact that the Time Lords are all clearly human fits right in perfectly. If Doctor Who suddenly developed a bigger budget and used CGI, however, than the humanness of approximately all the aliens with speaking parts would bug me quite a bit. Thankfully, the show was cancelled in 1989, so that'll clearly never happen.
So remember, no matter what planet he's supposed to come from, Superman is fully human, even if his weakness is krypton. (They do know krypton is a noble gas, right? Never mind.)