It seems to me, that 95% of all fandom-crushing events are based on Authors bein incapable of understanding the concept of "rare".

Avatar: The peak of abilities that only ,1% of people are capable of achieving: new forms of bending.
Aang is literally a god in a childs body etc. So, in Korra, they turned avatar into a slight boost, and new bending forms into a 9-5.

But Avatar is just the obvious example. I have seen so many Star Wars fans not being able to understand the ridiculous powerlevel an average Jedi actually has. Or, just the fact, that they are rare as fuck. Yes, there were thousands of them, but on a GALACTIC SCALE.