More than fantasy or even science fiction Ray Bradbury wrote horror and like so many great horror writers he was himself utterly without fear of anything. He wasn't afraid of looking uncool - he wasn't scared to openly love innocence or to be optimistic or to write sentimentally when he felt that way.
I'd say that after my father passed my writing changed it went deeper. Most would say 'matured' but I don't think I'd use that word in relation to my progress. I think 'change' is a little more accurate.