Imagine this: A few months ago, your father "passed away." Only less than one short month later, your mother decides to remarry. Not only does your mother, The Queen, remarry, but she marries your father's brother. Not only does all of this happen, but one day you hear that a ghost has requested your presence. Do you go and pay this apparition a visit? Hamlet of course does and discovers that his father was murdered by the current King, Claudius.
Would this make you a lunatic?
But then again, is it also correct to claim that Hamlet is a lunatic? Or does his circumstances, especially the fact that he is royalty, excuse him from this label?
Unfortunately, not every character in literature receives the same privileges.
Septimus Warren Smith in The Thing They Carried endured a similar fate. He was exposed to the horrors of War and suffered the consequences. However, the people in his novel did not feel the same empathy for Septimus as they did in Hamlet's novel.
Both authors, Shakespeare and Time O'Brien, touch on this idea of the ability a person has to feel compassionate for others. Hamlet and Septimus are similar in the way that they have both affected by their respective troubles, but the human mind is only so capable for forgiving certain characters if they feel they are worthy of it.