I think we need to split the behavior tag into what I've seen are the two common uses for it:
behavior - explain behavior of a pet
unwanted-behavior - refers to an undesirable behavior of a pet
Yes / No / Maybe / Abstain?
My sense is that every new visitor to the site, along with many regulars, would still select the behavior tag when talking about undesirable behavior, making the split a burden of work for the more active amongst us. That would also negate the value of the second tag since many wouldn't think to look for it.
I guess I don't see the gain with that, so I'd have to vote no on it. :)