Antigone is eager to bury her brother because her emotions and her duty coincide. This coinciding is strengthened by here fearless nature. Nothing deters her. She cares only about doing what is right according to the highest standards of humanity and of the gods. She wants to bury her brother as much as Creon wants to prevent his burial. She maintains her stand from beginning to end, willing to do and endure anything to accomplish her single-minded purpose.
Threats and warnings have no effect on Antigone. She argues that if it is a crime to bury her brother, it is a "holy" crime, decreed by a law higher than the decree of Creon. It is the law of the gods she must and will obey. She sees that her efforts may lead to death but it will be an honorable death.
Also, there is no doubt to Antigone that her foe Creon is operating not from higher principles, but from pride, hatred and revenge. Her resolve is strengthened by the overt evil of her foe. Antigone is the one who is doing he work of the gods, not Creon, who cares only about his pride and his power. The strange occurrences which accompany Antigone's second attempt to bury the body show that she is favored by the gods, that she is doing the right thing while Creon is doing the wrong thing. When Antigone is brought before Creon she fearlessly tells him that he is wrong, that his decree is meaningless in the face of the will of God.
In short, Antigone sees evidence in her heart and in the signs from gods that she should bury her brother. The obvious evil of Creon, instead of scaring her off, assures her she is right. Antigone shows herself to be selfless and dedicated to high personal and spiritual principles which are completely unfamiliar to Creon. Antigone lives and dies in honor, fearlessly dedicated to the highest principles of duty, loyalty and selflessness.
Hamlet's situation and nature are in stark contrast to those of Creon. As brave and determined as she is (...