Child custody orders are (usually) a paragon of compromise. The court tries to act in the best interests of the child, and that (usually) means including both parents in the custody arrangement. Unfortunately, compromise is another word for "everyone is unhappy settlement." Sometimes that unhappiness can lead parents down unwise paths.
You may have every justification for taking your child, the other parent is a bad influence, drinks too much, or is negligent in caring for the child. But, unless lives are in immediate danger, you should obey the court order. That means you cannot move to a new city or state and take the child with you. You cannot refuse to turn the child over when it is the other parent's custody time. If you fail to obey these orders, you could be found in violation of the law and charged with kidnapping or abduction.
If you are arrested, the other parent can often use it to modify the custody order and take sole custody of the child. Around 200,000 children are kidnapped by a family member every year. The government takes these offenses very seriously. The federal government even requires state courts to enforce custody orders from other states.
If you disagree with the court's decision, you need to work within the judicial system to obtain a modification. You cannot take your child and refuse to turn him or her over. Refusal to cooperate will only make things worse.
Are you trying to obtain a child custody modification order? Then you may want to contact a family law attorney for legal assistance. As illustrated above, disobeying court orders are serious and could result in serious criminal penalties. The solution to your child custody matter isn't taking it into your hands (that is a temporary and illusory solution at best). Instead, you need to work the within the legal system and obtain a modification legally. A lawyer can represent and guide you through the process.