Just because you are no longer a teenager, it doesn’t mean that you can’t act like one.  No matter what developmental psychologist, most of them allow for you to revert to a previous stage of development.  So when you see grown adults act like kids or teenagers – that’s what’s happening.  It’s natural.  It happens.

Being a kid or teenager is absolutely natural.  Now what you choose to do when you are adolescing – that’s a different blog post.