This story device cuts far deeper than Steve Barber's reference to Superman's ideal of "'G' for Goodness", because the test was so constant, and not even the Surfer was infalliable.
Actually, it were the "other" Steve (the ugly-dude avatar, I'm the dalmatian), but the point's agreed upon.
Of all the Marvel characters, Surfer and Nimoy... err.. Namor come the closest to icons-in-training. And possibly the Phoenix (all versions: green, Dark, burning, and white-chocolate). Being true to an ideal is, to me, a fundamental aspect of creating that mythos. The Surfer, in particular, suffers because of his dedication to that ideal, and his dreams and aspirations make him try for more. This is what separates the character from the icon. The icon represents something greater than themselves.
(This is also why, at the core, the characters of Star Trek, Star Wars and Alien are iconographic, while those in films such as Blade Runner and Close Encounters are not -- even though those are considered better films.)