I am often told that what we plan to do regarding our children and what we will end up doing will vary greatly. This stems from the idea that when we are overwhelmed, we resort to how we were taught by our parents in frustration. By that point it would take much determination to stay true to the parenting ideals made previously, assuming any research and reflection was even attempted beforehand. Although this scenario is quite common, I believe that it can be managed positively by first preparing oneself on how to deal with such overwhelming feelings that may distract from those parenting goals.
There are many reasons why a parent would feel overwhelmed and unfortunately it's the children who suffer from a parent’s lack of emotional control. By practicing positive stress-handling techniques, any situation can be positively overcome and can be turned into a life lesson for all those involved. Children have a way of bringing out the best and worst in a person and those difficult situations are great for learning about oneself and showing them how to deal acceptably with those emotions. Children learn from what they see, and the behaviour we dislike in them and scold them for is behaviour they might have essentially learned from us (yikes!). If we want to change the way we parent in order to raise happy, healthy, successful children, we must first change how we are within ourselves.
Perhaps some reasons parents give up their original choices is due to pressure from others, being unable to meet certain difficulties, or lack of preparation but I strongly believe that nothing worth accomplishing will be easy. It is up to the individual to decide whether the end result, or the journey, is worth the effort.