I've never seen a snake in real life that wasn't behind glass at a zoo (or behind handled by a zoo keeper while others were allowed to pet it) and most times at the zoo, they're not even moving, so I've never felt fear upon seeing one. However, if I went in my backyard and saw one slithering around, I'd probably freak out.
Worms, now them shits are terrifying. Had a kid put one in my hair when I was about 5 and it took hours to get out... in bits. So yeah, when it rains, I always watch where I walk. Bleh.