Sharks are single minded. They're ultra-efficient hunting, killing, and eating machines.
Dolphins are just as effective at hunting, yet are known for their intelligence and playful nature.
Sharks are respected and feared. No one wants to swim with one.
Dolphins are the life of the party. Everyone wants to swim with one.
Sharks mostly work alone.
Dolphins are extremely social, working in groups while fishing. They foster strong social ties.
Sharks can't stop moving.
Dolphins need to come up for air.
Shark skin is abraisive.
Dolphins are soft and slippery.
Sharks haven't evolved much in thousands of years.
Nature needs both.
...But I'd rather be a Dolphin.