What makes spiders scary to you personally?

[Twilight Sparkle97 402]

** I hate spiders. **

[Mallow Gloom 26]

I actually really like spiders, well, except baby ones because they are so small you almost can't see them- A summer or two ago a hundred or so hatched in my room and I needed to get them all out... they were everywhere 

[Brony Number 42 10,069]

A spider put me in the hospital for 2 days. 

[Sonic Shimmer 4,132]

I'm not scared of spiders but I live in the UK where they're generally all harmless (the False Widow being the only one that's potentially an exception).

[DixonTheAdversary 1,632]

Usually when they jump of the wall towards me is when I get startled.

[Shadowmoth2011 150]

It's mostly in the way they move. Oh sweet Celestia they're like walking disembodied hands tickling your walls!  I also don't like when they're particularly big...and hairy...they just look UNNATURAL