I believe that Tennysons works do represent the different positions of optimism and despair. In The Lady of Shalott, she is hoping to get out of the castle, but she dies on the way down. In Ulysses, the two ideas are represented again, but through different ways.
The lady in The Lady of Shalott is waiting for a prince to come and save her. A bowshot from her bower eaves, /He rode between the barley leaves describes her seeing Lancelot.
She climbs down from the tower to ride a boat down to Camelot and (since she is cursed) ages rapidly and dies in the boat- She floated down to Camelot; /And as the boathead wound along /The willowy hills and fields among, /They heard her singing her last song, /The Lady of Shalott.
In Ulysses, the persona loves going to battle, it gives him a sense of worth and something to do- And drunk delight of battle with my peers. He wants to go back out and fight, but there are no more wars, and his soul feels younger than his body. We are not now that strength which in old days /Moved earth and heaven, that which we are, we are- /One equal temper of heroic hearts, /Made weak by time and fate, but strong in will /To strive, to seek, to find, and not to yield.
Tennyson had some tragedies in his life, and wrote about them in his poetry. But like all humans there is always hope and optimism that things will change for the better.