There was a classic humor short story about that. A man visiting a third world country bought a potion from a street vendor, that would “make a dog’s tongue shrink, so it can talk. Just one tablespoon a week, and when you stop, the dog’s tongue will go back to normal.”
So he gave a spoonful to his dog. It worked, but the dog became a major pain, criticizing him, demanding things, talking to his friends behind his back and giving away secrets, and finally lying to his girlfriend so she stomped off and left him.
So he didn’t give the dog any more, though it kept demanding more. And the dog reverted back to his sweet, ignorant and pleasant personality. Then he remembered that the vendor said, “...when you stop...”, and understood why he was so sure he would stop.