Answer:
1. the death of Hamlet's father - Claudius
2. the death of Hamlet's father and the ensuing hasty marriage - Gertrude
3. Ophelia's rejection of Hamlet's love - Polonius
4. disappointment at not being named king after his father's death - Rosencrantz and Guildenstern.
Explanation:
Hamlet is a character who goes through many difficult situations, such as the murder of his father, the usurpation of the throne that belonged to his father, the marriage of his mother to the murderer, the rule and death of the woman he loves, the specter of father walking through the fantas and a highly shaken psychologist. All of these things make Hamlet have attitudes that are considered abnormal for the other characters who faithfully believe that Hamlet is crazy.
Hamlet is not crazy, but Claudius (the killer of Hamlet's father) believes that he went crazy because of his father's death. Gertrudes believes he is dead because of her marriage shortly after the death of Hamlet's father and her husband. Polonius believes that he is crazy for not having achieved the love of Ophelia and Rosencrantz and Guildenstern believe that he is crazy for not being his father's successor.
