why was hamlet upset with Gertrude

Hamlet was upset with Gertrude, his mother, because he believed that she had betrayed his father, King Hamlet, by marrying his uncle Claudius shortly after King Hamlet's death. Hamlet was also upset with Gertrude for not mourning his father's death for a longer period of time and for her apparent lack of understanding or concern for his grief. Additionally, Hamlet may have been upset with Gertrude for her role in the apparent breakdown of his family and for her refusal to see the truth of Claudius' actions.

Polonius advised Ophelia not to

Polonius advised Ophelia not to trust Hamlet's declarations of love and affection for her. He warned her that Hamlet's love may not be sincere and that he may take advantage of her innocence and purity. Polonius believed that Hamlet's feelings towards Ophelia were likely fleeting and insincere, and he urged Ophelia to protect herself and her reputation by being cautious and wary of Hamlet's advances. His advice ultimately contributed to the breakdown of Ophelia and Hamlet's relationship and to Ophelia's tragic fate.