I've had pet snakes my whole life, so I guess the answer is spiders. But, I'm not afraid of all spiders. Any web spider, jumping spider or most tarantulas are not scary. Wolf spiders and wood spiders freak me out, mostly because they are gross and could potentially be a brown recluse, whose bite I am scared of.
Almost thought this had to do with the game with how you capitalized FEAR.
I used to fear snakes but I don't anymore. As odd as this may sound Metal Gear actually helped with my phobia. People tend to forget that snakes fear us just as much as we fear them. People also tend to get creep out when snakes eat other animals but in reality that's just their way of survival just like how some of us may eat cows and pigs.
Spiders I've always feared though but snakes I absolutely love. If I could I would own one but my parents hate snakes.
I think people are lying when they say they're not concerned/afraid of either, if you see a poisonous spider or snake near you, you're not bright if you don't take fear or concern into account lol.
While I personally don't have a "fear" of either per-se, I DO take both with caution depending on the breed. A house spider is nothing, they can't penetrate your skin and can be killed easily, now a black widow on the other hand or wolf spider or tarantula anyone should take with caution for common sense reasons...their poison can kill you or harm you severe.
A snake, being as how there's more poisonous snakes out there then non...just don't go near it, if you step on it pray it's not a super poisonous one...lol. Overall, I'd take more caution with snakes in terms of the natural, outside world as it's hard to see them. A spider if they hear you coming will most likely move anyway, depending where you live black widows can live in a basement so it's all about where you live, Aussy also has some nasty ones that you have to worry about that can go into your house.
So honestly it depends where you live, the area. Where I live we have neither thankfully, but if it's poisonous and it can hurt me then I show logical concern, sometimes you have to fear or show concern over something unless you're just stupid and want to get bit.
Something about how Insects and Arachnids look just sends a shiver down my spine. At least with snakes they look familiar. Spiders just are so non human its freaky.
Being a huge Fallout fan nothing makes me cringe and rage like a pack of cazadors.