The problem when animals are too smart? They become too much like us. Take dolphins. Movies like Flipper and seeing them at Sea World makes us think they're just really cute. And they are! But they're also too damn smart. Smart enough to masturbate, smart enough for depression, smart enough for suicide, and for so many awful things that humans do too.
Watch ADHD do their reliably funny Scientifically Accurate bit on Flipper in the animation below.