My last thread inspired a new question. What do you feel qualifies as childish behavior? What distinguishes childish behavior from adult behavior?
Depends on what stage of childhood you are using as a reference. My two year old went through a horrible biting phase, thank goodness that's over! My 6-year-old is in a phase where he thinks knows how things work, knows the rules, and wants to make certain everyone else around him does too.
A lot of what I personally would call childish (in a negative way) is attention-getting behavior, or behavior that shows a lack of empathy for others, or an unsophisticated understanding of other people.
Children have some natural empathy but it takes a long time before they can really understand things from another's perspective; many adults aren't very good at this either.
Escapism can be childish, again in a negative way. (drugs, or anything that we use to escape responsibility.) Including, erm... this site.
Childish behavior that I think is positive and which adults would do well to remember is honesty, expressing exactly what one is feeling, and creativity. If a child is hurt, angry, jealous, happy, excited, they simply can't and don't hide it and so many adults play games and hide their feelings. Plus children are so richly imaginative, we adults have learned and been slammed by so many restrictions and painful experiences that we often sort of box ourselves in and set limits. Children don't understand limits, and in a way that is a very good thing.