It is normal to have days (or stretches of days) where things just seem to have fallen apart. It happens over and over again, with everything from sleeping to discipline. You just have to be consistent and plug through and then they go back to their normal, happy selves.
There are a few reasons for this behavior.
- You are allowing too many freedoms or too many choices (see BW II: Freedoms: http://babywisemom.blogspot.com/2008/01/babywise-ii-freedoms.html and The Choice Addiction (for Toddlers) : http://babywisemom.blogspot.com/2008/03/choice-addiction-for-toddlers.html). As I have said many times, misbehavior in your children is often really your fault. You are at the root of the problem. Once you change yourself, your child will follow suit. I think it happens because our child is being so good that we start to either relax our rules or offer more freedoms than our child is ready for. So first evaluate yourself.
- Disobedience is often in conjunction with your child learning a new skill. Some skills bring with them a whole new world of options. Take crawling or walking. Your child has new mobility and can reach new heights. There are things neither of you have had to address yet because they have been non-issues. So you need to address them. Other skills can bring a degree of danger. Take climbing stairs. Boundaries need to be set for when your child may and may not climb the stairs. Your child wants to work on these new skills. You just need to take some time and effort setting the new boundaries.
- It is just the way it is. People push the limit. For example, let's examine the behavior of an adult driving. You want to get from A to Z as fast as possible. You start out driving the posted speed limit. After some time, you start going 5 mph over. Then you start to go 7. Then you push it up to 10. Then you just don't even really have a regard for the posted speed limit. Then you get pulled over and pay a hefty fine. So you go back down to the posted speed limit. Many adults will find themselves soon pushing that limit again. It is in our nature to push limits. That doesn't mean it is what we should do or that we should accept the behavior from our kids, but it is what it is. It doesn't mean your child is as terrible person or that you are an incompetent parent, it just means that is going to happen sometimes.