The biggest problem with new terrainers today is that there are no new terrainers today.
Seriously, there's so few of us, and people don't have the same drive any longer, it
seems.
But yeah, impatience is certainly one of the mistakes, I also don't like how some tend
to overachieve, trying to make terrains with reflective water surfaces or other fancy
things when they don't even have the basics under control.