If a virtue is something difficult to maintain and necessary for the flourishing of  human society – then hopefulness qualifies.

It can be hard to keep going in a world where there is so much suffering in evidence.

It can be disheartening when the bad guys seems to win and the good guys go to the wall.

It can be difficult, as you grow and gain experience in the world to hold onto hope.

And still.

Most of the important things in the world have been accomplished by people who have kept on trying when there seemed to be no hope at all. ~ Dale Carnegie