Thats exactly it. Burn is right, every creature has its own personality.
I saw Electric Blue hermits for sale at my LFS. I came here and did a search and everyone here said they were reef safe. I went to the pet store, and a customer there was saying that his was so destructive he had to get rid of it. And then, the LFS owner said that every once in a while, one will come along that will terrorize a reef tank. But its rare. And a customer was agreeing that they never hurt his reef, and he had 4.
So its just luck, as it is, it seems, with a lot of these salt water critters. lol