Ramachandran: Religious experience might be extreme activity in the frontal lobes consistent with attributing emotional significance to everything – a grain of sand is seen as being as precious as our mother. We are in a state where all objects of experience are of infinite value.
Heidegger: Being is disclosed in boredom because we experience all as equally bland, uninteresting, and triggering no emotion.
So the opposite of boredom is not concern or emotional engagement but religious experience. Concern or absorption in work is a mean state between boredom and mysticism.