The hundreds of adults I now work with at camps and clinics each year are different. But they don't face it so cheerfully. When kids go to practice, they take it one day at a time. They just do what the coach tells them, and they're with their friends. To them, it's just playtime in a more structured environment.
Adults view it as work.
Many, particularly triathletes, feel pressured to swim better in a hurry. And, if they've been trying to swim on their own for several years, there are layers of bad habits on the slate to overcome. But there's one great equalizer. They are rapt and absorbed pupils, far more dedicated students than are most kids. And attention and motivation are the most important ingredients in learning new skills.