65 On Childishness vs. Child-likeness
The difference is that being childlike is a state of innocence and freshness, of non-seriousness, that lets you be more effective in the world.
On the other hand, being childish is a state of immaturity, of avoidance, where you intentionally sabotage your work, or social situations, with your "inner child" serving only as an excuse.
Also, those who are concerned about other people noticing their behaviour are being childish.
When you try to create a childlike attitude, you will almost always end up just being childish instead.
Real childlike nature comes naturally, out of meditation.
Finally, if your behaviour is making it more difficult for you to actually work in the world, or in the school, or if you are doing that behaviour as an excuse not to practice some kind of discipline, then it is probably childish behaviour.