1. The death of his father, King Hamlet. Hamlet's father died suddenly and mysteriously, and Hamlet is suspicious of his uncle Claudius's role in his death. He is also grieving the loss of his father and feels that he has been robbed of his inheritance.
2. His mother, Gertrude, marrying Claudius. Hamlet is furious that his mother has married his uncle so soon after his father's death. He sees this as a betrayal of his father and a sign of her lack of love for him.