When Opie develops a crush on Miss Crump ("Opie Loves Helen," Episode #132), he doesn't realize that he's stepping on Andy's toes. After all, Helen is Andy's girlfriend.
All's well that ends well, though. Once Opie understands his father's interest in Helen, he bows out. However, that's not to say that Andy's a better dancer. Andy sums up dancing skills: "I two-step a little."