Bringing up children is a minefield. Children are individuals and don't come with instruction manuals.
Its OK, if a mother (or father) once in a blue moon does something she regrets. Being occassionally shouted at or (shock! horror! even smacks a child) is not the end of the world. There is a problem if a parent thinks its OK to be violent on a regular basis. However most adults have turned out OK inspite of inferior parenting methods.
I think that if we try to be too perfect and follow supernanny/ Gina ford/ William Sear/ the dog nextdoor to letter you end up with a relationship with a book instead of your own child.