I think you can encounter all of the classical 7 sins in this hobby (and every where else as well).

Lust
Gluttony
Greed
Sloth
Wrath
Envy
Pride

We are all somewhat human. While we may believe we were created equal, we certainly don't finish there. Half the population is not as smart as the other half, and many have not the time, nor the opportunities to develop the skills or knowledge of the expert. The hobby is quite diverse today, so few experts cover the entire depth and breadth of today's RC. Most experts are not self selecting this title, but they are the guys that test fly a lot of new models for others, are there to trouble shoot a balky engine, and if you are really lucky instruct on how to fly. While the average instructor covers the bulk of primary instruction, an expert may still be training a new flier many years after that first solo on the finer points with the hope that this will ease his own burden at the local field.