- We're told that Joppa is suffering under a curse. Certainly Princess Andromeda is being put through a terrible ordeal personally, and that alone is probably enough to set the whole city on edge; but the first sight we see of Joppa is a big, bustling marketplace that seems quite prosperous, and it seems like the worst thing the common people are having to deal with themselves is all the marsh flies.
- They know that "Thetis, our patron goddess, is angry" over what Zeus did Calibos — that's got to be more than enough to throw a city into a constant state of panic. There's also the men who get burned at the stake, as Perseus observes, after failing to solve the riddle that Calibos and Thetis have forced Andromeda to use as an Engagement Challenge.
- Thetis probably can't hit them with anything too heavy over the Calibos thing, else she risk pissing off Zeus. But she can torment them in myriad different ways, like the flies, possibly other things like drought and misfortune, plus the whole thing with the princess. It's probably a case of "Nothing's gone quite right since the whole Calibos incident."
- Maybe it's a case of what you DON'T see invoking speculation and true horror. For all we know, there could have been plagues, rampant infanticide and cannibalism going on throughout the city.
Headscratchers / Clash of the Titans (1981)