I'm pretty sure that if I walked up to any of them on the street I would be pretty freaked out.
Well maybe not Catra, might be more like "how you doing"?
But if I had to pick a couple... Leech, huge mouth, lots of teeth, big sucker hands...yea that would do it.
I also imagine that anyone would be scared of Scare Glow. It's kinda his thing.