I know Ernest could be annoying, but Vern seriously treated him like shit, pushing him off ladders, mashing his fingers in windows, trying to fucking SET HIM ON FIRE WHAT THE FUCK VERN.
Vern was a total dick, but Earnest didn't have any other friends, so he put up with all that abuse. It all makes a sad sort of sense when you realize the fact that what they have is a textbook abusive relationship.