There were some things that didn't go well, some things I personally didn't agree with...
上手く行かなかったことは「Didn't go well」です。
納得の行かないことは「Things I don't agree with」(筋が通らない)と言います。
従って、「There were some things that didn't go well, some things I personally didn't agree with...」を提案しました。
質問者様の文書をそのまま訳しますと、「Thinking back on this past year, there were some things that didn't go well, and some things I personally didn't agree with.」
There were things that didn't work out or that I couldn't come to terms with.
「There were things that didn't work out or that I couldn't come to terms with.」と表現することができます。ここで「didn't work out」は「上手くいかなかった」という意味を持ち、「come to terms with」は「納得する」という意味ですが、この文脈では「納得いかなかった」という過去の状況に使います。「There were」は複数の出来事を指し、「things」は具体的な事柄ではなく、一般的な出来事を指す場合に使用されます。