I was down the Aaron Swartz rabbit-hole once again, and it made me notice how some of the interesting people are essentially the same kind in both childhood and adulthood.
In childhood, they do serious things and work with passion and think about things as if they were adults, and in adulthood too seem to be unconcerned by things most adults take too much seriously.
In other words, although their experience and worldview changes as they grow older, but an essential attitude of theirs remain the same. If it's fine to enjoy yourselves, then it's equally fine in both childhood and adulthood, and if you should be serious about thinking about things and the work you do, that should be equally valid in both cases as well.
This doesn't seem to be how most people behave.