My first awareness of Louis Armstrong was the day he died. Even my father, whom I never knew to have any musical interests whatsoever, remarked when the news came on the radio - nothing memorable. Just something along the lines of "how about that?"
Not having ever been much for jazz myself, I paid scant attention to Armstrong, and my general impression of him was that he was the Bill Cosby (from the pre-rape Cliff Huxtable era) of jazz: affable and non-threatening enough that lots of even conservative white people liked him. And he sang "What a Wonderful World."
And then I caught the Ken Burns Jazz series and saw a video clip of a performance of Armstrong at the end of the second episode. And wow. Now I got it.
I had no idea how important Armstrong was to the development of jazz, much as it took me years to learn how important Beethoven was to the development of the classical orchestra.
I have been very aware of how African Americans invented American culture though. I know this intellectually, through books and series like "Jazz" but it was only when I was outside of the United States that I really got it. I travelled to Ireland at the end of the last millennium because the company I worked for was based in Dublin. And while I was there, it hit me. Something was missing. And after some reflection I realized what it was - it was just too white in Ireland. Celtic culture certainly has its charm but it is missing that fundamental element of, for lack of a better word, "coolness." And that coolness derives from African American culture, so well encapsulated by jazz and by some forms of rock music too. It was a real revelation to me.
Speaking as I have been about the socio-biologists, I remembered Al Franken got off a good one against them at his 1996 appearance at the annual White House Correspondent dinner:
...also here tonight is Charles Murray, who I understand has been hard at work on a sequel to the Bell Curve entitled "Jazz, the Music Created by Morons."