Rav Wolbe writes (Ma'amerei Yemei Ratzon pg. 89) that the ninety eight curses mentioned in this week's parsha were written with a specific intention in mind. They reveal and clarify for Bnei Yisrael in exactly which aspect they have veered from Hashem's will. For example, the Torah tells us, "Because you did not serve Hashem your G-d with happiness . . . You will serve your enemies" (Devarim 28, 47-48). Hashem punishes measure for measure.
This middah is not limited to punishment. Chazal tell us that if one "passes over" his middos i.e. does not get riled up when someone wrongs him, Hashem will "pass over" his transgressions (Rosh Hashana 18a). This idea is alluded to by David Hamelech in Tehillim (121, 5) when he stated "Hashem is your shadow." Just as one's shadow mirrors his every action, so too, Hashem responds to us in a way that mimics our actions. If we open our hands to give tzedakah, He will open His hand and shower us with bounty. Similarly, if we act with kindness and compassion to those around us, He too will act with kindness and compassion toward us.
Din (judgment) is a frightening notion. How is one supposed to pass through the din of Rosh Hashana signed and sealed for a sweet year full of blessing? Chazal revealed to us the secret. You yourself decide how you will be judged! The way you act is the way Hashem acts with you. If we place an emphasis on acting with kindness and compassion toward others (even if they might have rubbed us the wrong way) we can be certain that Hashem will deal with us in a similar fashion!