Trying to convince myself with logic that a task is important or urgent usually ends up coming down to "do The Thing, because <bad consequence> will happen if you don't", which just activates my anxiety and gradually evolves the task into a claustrophobic threat.
Focusing on a positive reward doesn't help because the reward just turns into the thing that will be taken from me if I fail. Telling myself I'll get a treat becomes "do The Thing or the treat will be taken from you."