After spending much time in Wintergrasp continuously clicking "decline" quest, I realized there is no simple way to prevent every incoming quest that comes your way. Thus, Quest blocker was born.
Questblocker is a small, light weight addon that stops every incoming quest with a simple command!
Typing /qbon will enable this feature, and if you are needing to accept the quest in the moment, /qboff will disable it on the fly!
Questblocker will also notify you when unwelcomed quests attempt to take up your precious screen space.
All options can be seen using the /qb command.
/qbon
/qboff
/qbshow
/qbhide
/qbreverse