Arachne's pride is the reason of her downfall because instead of being grateful from the Goddess of crafts and wisdom she challenged her in order to find out who among them is better in the field of spinning and weaving. She did not even bother to acknowledge the existence and interference of the Goddess insead she continued to believe that she owes no one of her talents and skills. She was not just overly proud, but very ungrateful too for a mortal like her.