In the pantheon of hurdling, there are few jumps larger then the proverbial 'geek' hurdle. Of course some might say that 'nerd' hurdles is the correct term. I chose to ignore those people, as I hope you will as well. A 'geek' hurdle is the level of acceptability a concept can create in the common man-geek (or she-geek if you prefer.) It's the moment when the non-geeky general public tunes out of a science fiction movie, or starts to yawn on the genre tv show that just got canceled.
You know those moments in movies where the unexplained is explained? The super scientist gives you a thirty second explanation for why a certain tech works? Or how he figured out the planet is in danger? Most of the time, that moment is the pinnacle of the 'Geek Hurdle'. Of course you might have other moments, but a majority of the cringe worthy moments, that happen in a blockbuster happen in the exposition.
Here in an uncertain terms (feel free to argue) are the top ranking Geek Hurdles.
Yes freakin' Captain America I'm looking at you. Characters that have enhanced strength and speed due to a special serum, a rigorous training program, or some combination thereof. It's not to far out there, what with the accusations of doping in professional sports. Maybe they don't have a target on their chest, and they probably don't wield a shield, but they are generally believable.
Angels, Demons, and general biblical creatures. We live in a Judea Christian Western World were most people learn about the G-O-D when they are young, regardless of whether or not you are religious, most people will buy the big guy getting involved in some fantastic plot.
People with special abilities, people who are different from me and you, minus the Xavier school, are generally acceptable, while they begin to strain some credibility, most people will stick around.
Vampires / Werewolves
Sparkly or not, Vamps are a bit of a pill to swallow. At this point your movie/tv show has opened a whole gate way to bigger and crazier concepts. Granted your mind knows they aren't real, but who would argue that David Boreanz is fake? Not me.
Walking, running, stumbling, and mostly undead. Once you see these guys its over, forget about it. Realism is long gone, and its time to start throwing the undead kitchen sink into the mix. No one is watching zombies and expecting them to be completely believable. If they are they've gone insane, or are watching to many zombie movies.
You might think that the mysticism would be much lower on the list. Magic is to much of a cure-all. IE Marvel's "House of M". At it's most extreme, Magic trumps plot 9 times out of 10. No matter how impressive, Magic is a costly element to add to any story.
They used to be interesting, back before Star Trek, Babylon 5, and SG1 ruined them for everyone. They've become watered down, overused, walking cliche's. When they are used these days people yawn, become disinterested, or they generally recall post traumatic stress from the last India Jones movie. They always miraculously speak out language, or we speak theirs, or there's a translator, or insert universal language trope here. Even the new Jupiter Ascending with it's exciting visuals, and interesting plot, is groan inducing at the very mention of Aliens.
Where the hurdle is for you might vary, and it's possible that your equation might allow for aliens but scoff at super soldiers... whatever your hurdle, try getting over it, inevitably there are some really nice things to enjoy on the other side.