Athena wants Odysseus to disguise himself because she knows that it is in his nature to want to know the exact attitudes and crimes of those who took advantage of his disappearance. She wants him to be in disguise until he knows exactly what each suitors crime is and to develop a way to appropriately punish them for their behavior. This way Odysseus could also test his servants and his family for their loyalty as well as testing the suitors for their crimes. A deception would also make his homecoming more dramatic than if he just entered the palace and announced he was home. Finally, it was safer for him to enter in disguise. The suitors were not going to be happy that he had returned and they outnumbered him. By using a disguise, Odysseus could use his cleverness and timing to bear on the situation and insure a good outcome for himself and his family.