Naaman's problem was that he thought he knew the score -- important men do the important things in important ways -- but he was wrong.
That's not to say unimportant men are always better.
The story of Naaman continues after his healing, with Elisha refusing all gifts and approving Naaman's plan to worship only the LORD (with the help of some dirt from around Elisha's house) while still bowing when the King of Aram bows in the temple of Rimmon.
Although Elisha sends Naaman home in peace, Elisha's servant Gehazi figures he should grift something from the still-grateful Aramean. He cons Naaman, then lies to Elisha about it; when all is said and done, he has gained:
two talents silver
two festal garments
leprosy for himself and his descendants forever
A memorable day.
If Naaman is an example of learning to let God act in your life in ways you have not spelled out for Him ahead of time, Gehazi is an example of not learning even as you see God acting in the lives of those around you. He is an antitype of Judas, selling something holy (in his case, the reputation of Elisha) for monetary gain, and finding it a bad bargain.