My mother frequently rewrites history - both hers and mine.
One of the more hilarious examples was when she swore I'd "never" cried as a baby. I dug into a stack of old photos and came up with several pictures of my infant self crying. "Oh," says my mum, "Well, that was your father's fault."
I'm sure I was a perfectly normal infant, who cried as much as any infant cries (which is to say - a lot).
Less amusing was when she concocted a completely false "tough-love" story about how she'd kicked me out of the house as a teenager. And told it to her university class. And then told me! When I told her in detail what I remembered about that day, she got very upset and refused to continue the conversation any further. She said it was, "too painful."
For the record, I walked out after an argument. I wasn't thrown out. And yes, it was a very painful and frightening day for her. But, even knowing her tendency to reinvent things, I was still surprised at how thoroughly she got it wrong.
When I was a kid, I used to wonder quite seriously if I was insane, because my version of events often didn't match my mother's at all. However, as I got older, my friends - and sometimes even my mother's friends! - would confirm my observations and assure me that things really had happened the way I thought they did. Thanks to them, I'm a lot more confident now.
The interesting thing is, my mother really believes the stories she tells. She's terribly earnest and honest. Just... wrong, a lot of the time.
To answer the original question: My mother thinks my childhood was much worse than I remember it being. I wish I could talk to her about it some time, but every time I try to bring it up, she dissolves into a puddle of guilt and anger. It's unfortunate.