This is going back almost before my time as a reader, but I never understood why in GREEN LANTERN 49 (December 1966), they had Hal Jordan quit his job and leave Coast City. This is something that could have happened in a Marvel title--and maybe that's why they did it--but it made Hal look weak. After this he floats from job to job and doesn't have a consistent supporting cast (no Carol, no Tom). Because Hal is aimless it makes the book look aimless. I think this is the thing that undermined the title. And it's actually something Hal could never fully recover from.