What a huge question, Jasper! And practically unanswerable, though I think you've had a good shot, Liamsmum and certainly a bit of me-time is a very good idea IME, Monnie.
I work with parents- mostly mums- and young children who are having difficulties and I also have quite a few friends/acquaintances with kids, not to mention spending vast stretches of my time surfing on Mumsnet(!), so I meet and hear of lots and lots of families, one way or another. I assure you it's EXTREMELY rare to find mums who don't want the very, very best for their children. I really can't emphasize that enough, I suppose because, if I'm honest, it was a bit of a revelation to me. I can't tell you how many times I've walked into really very grim homes (badly maintained, poorly furnished, postage stamp sized places, often housing people with profound health, emotional or social needs- homes that are in essence the 21st century equivalent of the hovels of Dickensian disgrace) which are leavened only by the love and care lavished on the children's room, toys, food, equipment and primarily, of course, the children themselves. I've met some superb mums in this way- people whom I admire immensely. I've also met a small minority of people who were on the cusp of being unable to be good parents because their situation was so unbearably overwhelming for them that they could not cope with their child(ren).
I suppose what I'm saying with this ramble is that I believe being a good mum is sometimes about there being suitable conditions for a parent's natural wish to love and nurture their child to flourish- having decent housing and support, access to a good education, good health care, not living in poverty etc. Once these things are in place we can argue about Gina Ford or not, private vs. State education, smacking or not, Caesarean sections leading to ADHD vs. natural birth leading to a sore fanny, breastfeeding vs. bottle-feeding, authoritarian rule setting vs. permissive wishy-washyness till the cows come home. We can have great fun speculating about how all these affect our children and our status as good mothers. The truth is that some of these probably don't affect it very much at all, no matter how heated we all get about how very right we are, because, IMO, Mumsnetters' kids are, in general, likely to do just fine in life and reflect much glory on their parents! Why? Well- their mums are obviously interested in them and in childhood issues generally otherwise they wouldn't become addicted to Mumsnet. The fact that Mumsnetters are an articulate and supportive bunch and- unlike, I think, 86% of the population of GB- have regular access to a computer seems to me to indicate that they are also comparatively rich in any or all of the following: money, intelligence, education, employability. This means that their kids are unlikely to suffer extensive social hardship and will therefore get the chance to bask in their parents' love, howsoever this may be expressed, and grow up great.
What are your own thoughts, Jasper?