I think I understand where U2Kitten was coming from. Every mother I know, from a single lesbian doctor to a stay-at-home ultra-Orthodox mother of six, laughs knowingly and sheepishly when the question of 'how mothering changed your views on mothering' comes up. It's like other relationship-based endeavours: what might sound eminently righteous and sensible when you're sitting in the bleachers, analysing things from a distance, is totally different from what works when you're out there in 'real-time'--with sibling rivalries, schoolyard bullies, raging hormones, medical crises, suppressed resentments, overwhelmed teachers, marital tensions, and financial woes all piling atop each other at once. You won't have time to consult your '101 Things A Good Mother Mustn't Do' list--nor is the resulting guilt trip likely to help matters. Besides, that actually takes the focus off where it should be, namely on raising decent, fair, good-hearted children with a will to give something back to their world.
I think mothers are also (understandably) more sensitive to the judgmentality implicit in these kinds of lists. By definition, a list of 'good mother' attributes suggests those who don't fulfill its criteria are 'bad mothers,' even if only on occasion. And there's no shortage of Twelve-Step 'toxic parent' gurus around to fuel mothers' fears that parenting is some sort of perilous minefield, where one unwitting slip-up from you could emotionally mutilate your child permanently. (This goes for fathers too, of course...though lists of 'good father' traits tend to be far less exhaustive and exacting.)
Personally, I don't consider it my right or place to judge whether my mother and father were 'good' parents or not. They certainly made some mistakes; so did I. They said and did a few things that were quite hurtful; so did I. My mistakes never stopped them from believing in and loving me, though, and I feel the same way towards them. That kind of faith in one another is far more precious than anything reducible to a list of dos and don'ts.