I do believe in the phrase "they did the best they could." My mother's family of origin, plus what most of the family believes is an underlying but undiagnosed mental illness, did not exactly give her tools to be a good parent in most senses of the word. But. But these are the tools she had to work with: mental illness that caused her to explode in fits of rage then turn on a dime and be sweet and loving, leading to a person who was utterly unreliable (in all senses of the word - emotionally, physically, and practically); abject dejection at who she was with so little self esteem that every encounter was a source of terrifying fear for her which she attempted to cover up by being a bully; drinking to numb the internal pain.
Not exactly what one might call an ideal parent. But that was what she had to work with. She did the best she could. Was it good? No. Was it right? No. It cost my father his career eventually. The fallout on myself and my sister was severe. 15+ years of therapy and I am able to function pretty happily now. My sister? No therapy - still functions at about the same level she did when she was living at home, but substitute multiple husbands/ex-husbands for parents.
My father? He was raised an ACoA, he was emotionally and physically beaten down. This is the model he had of parenting. He did a better job of controlling his issues - until he retired. Now? Not so much. He also had not-so-great tools to work with. He did the best he could. And now, on top of his own issues that he brought to the marriage, he also carries severe guilt about not protecting us from our mother. He couldn't have. At the time we were young, divorce meant mothers got custody unless they could institutionalize the mother. She wasn't quite that bad (yet). So he stayed to prevent us from being raised only by her.
He did do the best he could with the tools available to him at the time. As did my mother. Was it damaging? yes. Was it good parenting? no. Did they have the *ability* to do any better than what they did? nope. Does it matter now? No, not really. As Mike pointed out - it doesn't matter what my parents did that got me to where I am today. The question is not "did they do their best?", the question is: Where do I want to go from here?
I chose to let go of the wondering. It makes no difference to me how they ended up the way they did. I didn't cause it, I couldn't control it and I couldn't cure it. I can not change anyone except myself. So if I am unhappy, I need to figure out how *I* can make myself happy - not how I can try to force others to give me what I need. I needed stability - so I lived utterly alone for a period of some years where I didn't have outside influences interrupting me. I needed to feel safe - again, living alone (with my dogs) I was safe (or felt safe). I needed to find peace. I found it through many years of therapy.
Did my parents do the best they could? Yes, I honestly believe that they did. Could someone else have done better? Probably. But I didn't have someone else as parents, and it doesn't matter now/today anyway, as I am where I am and I have myself to work with. I have nothing but pity for my mother, who led a truly tragic life (and still does). I have sympathy for my father, who wants to lead a different style of life but feels trapped in the one he's in and has no idea how to get out of it. I have no love for my mother - she never did anything to engender that emotion in me. I love my father, but avoid him as much as possible when he's been drinking.
But I do feel that they did the best they could. Both were damaged human beings, both did what they could given the damage they carried with them.