Brilliant posts and links again.
The 'excusing' thing is hard to work through, isn't it? Having known ALL MY LIFE how hard things were for my mother - she made sure everyone knew! - I found it impossible difficult to feel angry enough at her. Then I worked out that this hard life was the result of her choices, which she kept on making. One of those choices was to blame me, her child, for much of what was wrong. Another was to keep us all playing happy families with a violent sociopath. These are not the choices of a woman who is capable of being a mother.
I had this out with her. She told me all her excuses, of course, and I pointed out that, while I was her child, she expected a little girl to deal with her adult problems. I asked if she could see how unfair that was. Se said yes, she said sorry, and she kept going on about how she was the best mother she could be under her circumstances. Well, I know she was the best mother she could be - I have to assume she did her best but that doesn't mean my childhood was any less violent, miserable or lonely for it. After this I found it easier to feel angry although it was still a long time coming.
Since then, I find I still make allowances for her weakness (her madness, actually) and empathise with the undoubtedly trying times she's lived through.The difference is that I no longer feel these as excuses or justifications for the shitty childhood she inflicted on me. She is an 80-year-old woman who, like many others, suffered through the war and the years afterwards. Like many young mothers in the 50s-60s, she would have faced much difficulty and disapproval had she left my dad but she was professionally qualified and could have hacked it. Like many abused wives, she loved her husband and could not imagine leaving him. I understand all this and I see her as I do any batty older woman who's lived that life - happy she's now in easier times, and sad for some of the things she went through.
I understand it, but this understanding does NOT change my misfortune; it doesn't in any way mitigate the influences that have blighted my adult life. In fact, it made them worse - as long as I considered her 'reasons' as valid excuses, I continued to apply her values and excuses to myself and my life.
Many people don't get this. I've had aunts, siblings and various friends trying to paint me as unfair or unsympathetic. I'm not. I tell them I understand it all, but I am still left with the consequences. I tell them I've forgiven her. I have, but probably not in the way they mean. I've forgiven her because there's no point in holding onto blame. I have detached.
My processes are nowhere near finished yet and things might change again. I thought it might be useful for somebody else to see where I'm coming from wrt my mother and forgiveness.
Mizzy, I did your beautiful boat visualisation and realised I needed to put more people in it than my lakeside rowing boat could hold! (Resisting the temptation to let them all sink) I put them on an ocean-going liner instead.
As I stood on a busy Mediterranean quayside, squinting up in the sunshine to wave them off, I couldn't help noticing how they were already beginning their posturings, bringing others into their webs and jostling for power 
I was hoping to feel sad but, by the time the ship had untied, I was in fits of laughter!
Think I'll go and have a cold beer in one of those quayside cafes 