Good parenting and child care encompasses many elements, from communicating to teaching and from showing love to keeping the child safe. The trouble is that few parents are actually taught how to be good parents; they simply have to wing it. And their own upbringing is usually a major factor in how they raise their child, whether they want it to be or not.
When all seems to go well, most parents cope and with the resilience that children have, they turn out okay in the end. That is not to say many adults could not have benefited in some way from their parents doing something different when they were young. However, if love is shown to a child, that is one of the main things to ensure they become steady and reliable adults, with much to give to society.