A Newsweek article called In Defense of Children Behaving Badly, whose point is that little kids sometimes behave badly, but that doesn't mean they always will. He points to a meta-study saying* that good or bad behavior in kindergarten is pretty much uncorrelated with later school performance.
*The document at the link says DO NOT CITE OR QUOTE WITHOUT PERMISSION. To heck with them. How can you put something on the internet and try to keep it from being cited or quoted? Information wants to be free.