Dreugh quite possibly. No matter how strong my character is, I
always get an irrational horror into my backbone when the battle music starts while in the water. I feel so defenseless in there. Slaughterfishes just nibble your toes a little, but it's always a possibility the attacker is a big bad Dreugh who hits hard.
Cliff racers I don't even hate myself. They belong to the game, they are a big part of the world.
But yeah, they can be quite a nuisance.