I work at PetCo as well, and I can't say that any other job makes me more depressed with the stupidity of people. Not exactly myths, but I've heard

1) My ball python only likes fuzzies, even though she's 7 years old.

2) My 2 month old ball doesn't like to open his mouth all the way, so I'll only give him pinkies.

3) A ball python ate my friend's chihuahua...and a boa will eat you if you don't feed it every 5 days.

4) Ball pythons don't have fangs because they were removed surgically for safe keeping.

And don't try to give them any advice...because they'll just roll their eyes at you and ignore it. "My animal is alive, so it must be healthy and happy." Its pitiful.