The difference between retrievers and terriers

I had some butter on my fingers and decided to let the dogs each lick one. When I offered my finger to Dixie, the blind black lab from Alabama, it was if it were being cleaned by the softest of butterfly wings, but when I gave my fingers to Billy and Spoon, it was as if I had plunged them into waters infested by piranhas in a deskeletonizing feeding frenzy. I expected nothing but white bone when I pulled my hand back.