Frodo
Riot
Frodo does not know how to deal with his young cousins, Merry and Pippin. Merry is intelligent, more intelligent than Frodo, but when paired with Pippin, he uses that intelligence to create mischief. He knows his cousins want nothing more than to get simple pleasures from their mischief, and he knows they mean no harm, but he fears that one day they will get themselves in farther than they had wished and will face grave consequences. He does not want to hurt his cousins. He wants to keep them safe, out of danger. But they keep hurling themselves into it.
Right
He wants to do the right thing. He has been entrusted with a serious mission suddenly thrust upon him, and he knows that the fate of the world rests upon his small shoulders. It is up to him to decide what to do, and he wants to be in the right. He knows that the journey will test him. The journey will push his will and his moral compass. But he must keep a clear mind and do what his heart knows to be the right thing to do, no matter what the world throws at him along the way.
Influence
He is tested in ways he could have never imagined before. It seems to control him in ways that are unfamiliar to him. His actions are foreign, his thoughts wrong. He can barely go on. He tries to fight the influence, he truly does. But he is not strong enough. He is stronger than he thought, but not as strong as the others thought him to be. He lets the will of the Ring take over, guiding his actions by its own will. But enough of him is left to have some of his own influence. Enough to destroy it.
Healer
Frodo is not learned in the ways of healing. When he returns, he trusts the Elves of Rivendell to heal him. Their work is fantastic, but he can still feel the scars. He still hurts. The pain from his journey, though dull, is still there. He tries to return to a life of normality, but it isn't the same, especially with the pain in his shoulder constantly reminding him of everything he's been through. The others are quick to adjust back, but he cannot. He has been through too much, more than the others can imagine, to ever fully heal.
Closure
He cannot live normally. The memories of his journey, especially the painful ones, continue to haunt him. He is unable to live with civilians who have no idea what he's been through. So when Gandalf offers him a chance at a new life, he takes it. He does not tell the others until he is almost gone. He wants to minimize their suffering. They cry. He cries. Sam cries a lot. But he is not sad. In the new land, he can forget about his journey and suffering and start anew. This part of his life will finally be closed.