The sadest, and most challenging aspect of parenting is that we can only parent as well as the limitations in our personalities allow. It helps to read and learn about parenting, and to use what we didn't like about our parents' parenting to guide us toward improvements. Most educated parents do this. But wherever our vulnerabilities are, whatever ways we were hurt and haven't healed, is where we will hurt our children.
This is why it is so important to be aware of those vulnerabilities, heal what we can, and work around what we can't. Often, the vulnerabilites are memories of not being treated well by our parents when we acted a certain way that our child is now acting. For example, my son is very sensitive, and very intense. I was the same way as a child, and my parents never understood what to do for my sensitivities and intensity. When my son displays the same traits, he deserves my compassion, and usually gets it. But there have been times, when I haven't done any better than my parents.
One classic time this happened when he was young, was when i was stressed, or in a hurry, and his socks just didn't feel right in his shoes. He would throw his shoes off in a screaming fit over and over until I had no patience, or compassion left in me. It no longer mattered to me how uncomfortable he was, because then I was so uncomfortable. At those moments, it was as if I understood as little about his sensitivity and intensity as my parents understood about mine. This wound in me that came from my parents' not understanding prevented me from being the kind of parent I wanted to be. Now that I understand all this, though, I can have compassion for myself, and my son, and work around these situation creatively, (like investing only in socks that work for him, and not rushing him to put them on) so that we don't have to butt heads. So, like every parent, when my own childhood wounds are triggered, I am at my worst as a parent. This is why resolving those childhood wounds is so important for parents.
Most of us want to be great parents, and better than our parents. It is one of many human experiences of humility to find ourselves making mistakes in this most important thing we ever do. Humility can be very comforting if we know what to do with it, or it can trigger the horrible feeling of humiliation if we don't. This is one of the many ways that parenting is a spiritual practice, whether or not we think in those terms. Any kind of spiritual path should remind us that while we are wonderful and loved, we are all limited. If we can recognize that NOBODY is a perfect parent, and the ones that come closest have easy kids by nature, we can join the humble human race of imperfect beings. We can realize we are in good company. There is comfort in making peace with our limitations as parents. Of course we must take responsibility for what we do and don't do that affects our children. To have peace, we have to know we are as honest with ourselves as possible about our mistakes, get help when we need it, and put ourselves in our children's shoes to understand how they feel. We can do everything in our power to be the best parents we can be, and recognize that even that will be "good enough," but not flawless.