Had totally forgotten the 4 D's when something incoming crops up:
Can you do this right away, immediately, within 2 minutes? If so, do it.
Can it wait? Is it "burning down house" urgent? If not, mark as unread again, revisit later when you have dealt with urgent things
Is there someone you can delegate this to? If so, delegate it.
Is this someone/something wasting your valuable time & resource? If so, tell them you can't deal with this.
Always remember it is about YOU not them. They (whoever "they" are) don't know your full workload, priority list etc, so you need to make your task list work for you or fall over.