I know exactly what you mean! I also have the same thought sometimes haha. Or maybe just our receptors are developing still and fire off and cause little kids to be like that haha idk!
I'm pretty sure that "think like kids" has different connotations to us. What OP probably does not mean is "being pointless, silly, absurd, or in any other demeaning way," but rather, curious, easily excitable, knowledge-craving, intense about everything.