Yes, we are not perfect but we should have a desire to do God's will. Even when we desire to obey God and to be good parents, we will make mistakes in judgement. This recognition of our own imperfection should cause us to trust God even more in the discharge of our responsibility as parents (c.f., Psa. 127:1-2).
We do not intentionally train our children to be bad. But if we do nothing when our children misbehave then we inadvertently set the standards of acceptable behaviour because our children would think that what they had done was acceptable. This is negative parenting by default.
The longer a child is allowed to grow up unrestrained, the more he becomes enslaved to the self indulgence of his desires. Proverbs 19:18 states "Discipline your son while there is hope, and do not desire his death." This is a warning against negative parenting by default ... hinting at the possibility of reaching a point in time when it is too late ... when the child is too set in his foolish ways (c.f., Prov. 23:13-14). Moreover, it becomes increasingly difficult to administer the rod as the child grows older, bigger, stronger (than his parents) and more independent.
It is important to recognise that conflict is inevitable because two wills are involved ... that of the parent and of the child. For the sake of our children, we must overcome our tendency to avoid conflicts to confront our children whenever they misbehave. "He who spares his rod hates his son, but he who loves him disciplines him diligently." (Prov. 13:24). As parents, we cannot see our children heading towards destruction and do nothing!
The child may say, "I hate you!" but this is soon forgotten. What he remembers is that you have set boundaries for his behaviour and thus given him security and protection from his own self indulgence. Hebrews 12:9 states, "... we have all had human fathers who disciplined us and we respected them for it ..." because we know that discipline is an expression of their love and concern for us. Likewise, our children know that we care enough to confront them.
Proverbs 29:15 states "The rod and reproof give wisdom, but a child who gets his own way brings shame to his mother." Be steadfast in confronting your strong-willed child. View each confrontation as an opportunity to teach your child. Do not give up in aligning him to the ways of the LORD for in due time you shall experience joy as you see the fruit of an obedient child determined to do right (Prov. 17:25 c.f. 29:17).
Proverbs 22:15 encourages parents to apply the discipline of the rod to drive foolishness out of our children so that they will not follow a path of destruction (Prov. 23:13-14). The rod serves as a painful warning and acts as a deterrent to help the child control himself until he can restrain or push himself to do things that are not his choice by nature or desire. If children do not learn to obey their parents then it would be difficult for them to obey God.