While misbehavior can be downright maddening, realize that all kids act inappropriately and defiantly sometimes. Testing boundaries, asserting opinions and independence and showing curiosity about forbidden things are natural parts of development. If your child frequently misbehaves, though, you need to figure out exactly what's causing it in order to correct it in an instructive, effective manner. Look for common denominators and other clues to help you get to the bottom of things.
Need for Attention
Arguably the most common problem causing frequent misbehavior in children is the need for attention. Kids need lots of attention to socialize them, prevent under-stimulation, show them they're loved and valued and otherwise promote healthy development. Unfortunately, busy adult lives often mean neglected children. Plus, parents are particularly likely to ignore kids when they're behaving well and playing nicely on their own. Children who aren't getting positive attention, though, quickly start preferring negative attention to no attention at all. So, they act out, content to get yelled at in lieu of being treated like they're forgotten or unimportant.
While you might think of stress as a grown-up problem, it affects kids, too. All sorts of situations can stress a kid out and prompt frequent misbehavior. Major changes to routine or environment are often to blame. These might include moving, a new sibling, starting day care or school, a parent's new schedule, separation or divorce, death of a family member, an extended period of bad weather, being left with a new babysitter or countless other things. Stress also arises from specific situations, like bullying, abuse, feeling isolated, unrealistic expectations from parents or illness. Not getting enough sleep -- which itself has numerous possible causes -- is also known to cause ongoing stress and behavioral problems.
As they age, kids discover their own likes and dislikes, identify as individuals and desire self-determination. This invariably prompts power struggles between children and their caregivers. While some kids remain more tame about it, others are more outspoken; behavior and misbehavior varies widely among individual children. Additionally, as they grow and develop, children go through "phases," which can be veritable roller coaster rides of good and bad behavior or calmness and tantrums. While this is perfectly normal, when parents don't manage bad behavior in a consistent and constructive manner, it greatly exacerbates the problem.
In the face of frequent misbehavior, it's tempting for parents to think there must be some sort of disorder at work. While attention seeking and other problems are probably more likely, a variety of medical or psychological problems could be to blame for ongoing behavioral issues. If your child has any health troubles causing chronic discomfort or pain, it may result in acting out, especially when there's an inability to properly communicate what's going on. Disorders on the autism spectrum, attention-deficit hyperactivity disorder, oppositional defiant disorder, frustration from learning disabilities and other possibilities exist, too; consult your pediatrician if you suspect your child has any health concern.