This Shabbat is Shabbat Zakhor, the sabbath before Purim, which often coincides with Parashat Tetzaveh. The connection between the maftir aliyah and Haftorah and the holiday of Purim on Shabbat Zakhor is Amalek and Haman. Haman was a descendant of Amalek. Both of them are evil characters and people who remain in our memory from the Biblical commandment to remember Amalek and the act of making noise during the recitation Haman's name. Considering that these figures are people who sought to hurt the Israelites, why is it so important to remember them? Every preschool kid with a knowledge of the Purim story knows about Haman, sings songs about his three cornered hat, and makes hamantashen.
In the Haftorah reading, from the book of Samuel, there is a commandment to destroy Amalek, all the people and children with him, and his animals. As modern readers, even if justified, this commandment is very harsh. Reb Simha Bunim of Pzhisha, a Hasidic 19th century rabbi, commented that the commandment is in the singular rather than in the plural. He understood this to mean that one nation should destroy another nation, but rather the commandment is for each individual to search and destroy the Amalekite tendencies within ourselves.
Perhaps one reason why we remember our enemies so vividly is because we want to distance ourselves from the evil inclination that exists within us. May we all seek out the goodness in our hearts and banish our ill feelings this Shabbat.