We aren't 100% guilty of our evil deeds. We have many excuses, and Hashem might accept them. Just think about the powerful yetzer hara, negative human tendencies, bad habits, negative influences around us, and more. However, Hashem asks, "I understand that you failed. I understand that you erred. After all, you are human, and the test is very great. But why don't you regret what you did? Why are you placid, feeling that all is well? You should at least regret your sins."
Rebbe Bunim of Peshischa zt'l taught that on Rosh Hashanah and Yom Kippur, we are judged primarily to see whether we regret our aveiros.
The Midrash (Naso 13:3) writes, "It states (Mishlei 29:23), תשפילנו אדם גאות, 'Adam's downfall was his haughtiness.' Hakadosh Baruch Hu told him to do teshuvah after he ate from the eitz hadaas, and Adam replied, 'I don't want..."
