I've known for a long, long time that my aunt(mom's sister) and my aunt's husband never really liked me. My mom is still in denial about it. Both are dead now and I didn't attend their funerals.
My Great Uncle Harry, who the dog is named after, didn't like me. When I was 5, I excitedly told him he looked like a frog. He didn't like that and never forgave me. The sad thing is, I was really into frogs at the time and I remember thinking there was nothing I was more happy about than to have an uncle who looked like a frog. When he died, it didn't have any effect on me one way or another because we didn't have relationship.
Zack, like you, I also had an aunt, my mother's sister, who didn't like me. I don't know how you felt about her but for me, the feeling was mutual. She was not a nice woman and I felt sorry for her children. So, when she died, again, no effect on me. Just like people we meet, not all family members are going to like us. I made my peace with that concept a long time ago,
Both my aunt and uncle I'm sure was nice people. They only did anything for me because of my mom. They treated my dad much the same way although he helped both as they were dying from cancer.
I had a similar situation with my grandfather. I said something to him once in (understandable) anger and he never forgave me. Punishment did not fit the crime. We both lost much because of either his inability or unwillingness to forgive.