Hamlet's main existence in the play is as a son - loyal to the memory of his father, disgusted with his mother's betrayal of her husaband's memory. His first soliloquy reveals his despair at the loss of his father ("So excellent a king") and his mother's treachery in marrying Claudius ("a beast...would have mourned longer").

Yet Hamlet can never quite bring himself to  avenge his father.  He speaks of his father with loyalty and admiration, but his language shows his deepest feeling to be disquietude at his mother's relationship with Claudius ("reechy kisses") and in the end it is Gertrude's death, not King Hamlet's, that finally pushes him into killing Claudius.