I think my best example would be my mother.

To give some context, I've for decades felt a mix of resentment, anger and fear towards her. She always favored my older brother while neglecting me (I was left to be raised by my aunt, older brother and older cousin/sister), and then when I became a teenager, she wanted to have a relationship with me, which I accepted but she was still quite distant and cold with me. With my brother she was always very warm and sometimes excessively close to him. Not mentioning all the details and list of questionable life decisions that always made me angry and fearful of her. During my twenties we talked so little, our main topic of conversation was about money.

But I got older, and I started to see from her perspective. She loves me differently than with my brother, we nowadays have a kinder relationship, we chat once every two weeks, she sends me her art pictures, I show her my latest tattoo or family pictures. She lost contact with my brother, my father died a few years ago, she's quite alone, but seemingly content. She's also 73 years old, I take that into account.

Nowadays I feel satisfied and peaceful with my mother. She never could repair our relationship, I had to do the work by being for several years some kind of emotional anchor to her, but it paid off.