One definition of maturity: the point at which nothing surprises you any more.
I don’t mean maturity is losing one’s sense of wonder. I mean that you are no longer shocked at the unusual, unlikely or bizarre, not because you expect or condone it, but because you’ve lived long enough to reach the conclusion that as long as it doesn’t violate natural laws, anything is possible.
Some of the biggest shocks in my life have come from the least likely people. I haven’t become cynical, but I tend to qualify my statements by saying “I don’t think so…but anything is possible…”
Immaturity is thinking something can’t be (when it can) or someone can’t be possible of doing something (when they can). Immaturity is being too certain of what is possible or impossible.
The upside is that maturity increases rather than decreases one’s sense of wonder.